system.events - ClickHouse Documentation

Querying in ClickHouse CloudThe data in this system table is held locally on each node in ClickHouse Cloud. Obtaining a complete view of all data, therefore, requires the clusterAllReplicas function. See here for further details.

Description

Contains information about the number of events that have occurred in the system. For example, in the table, you can find how many SELECT queries were processed since the ClickHouse server started.

Columns

event (String) — Event name.
value (UInt64) — Number of events occurred.
description (String) — Event description.

Aliases:

name — Alias for event.

Example

SELECT * FROM system.events LIMIT 5

┌─event─────────────────────────────────┬─value─┬─description────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│ Query                                 │    12 │ Number of queries to be interpreted and potentially executed. Does not include queries that failed to parse or were rejected due to AST size limits, quota limits or limits on the number of simultaneously running queries. May include internal queries initiated by ClickHouse itself. Does not count subqueries.                  │
│ SelectQuery                           │     8 │ Same as Query, but only for SELECT queries.                                                                                                                                                                                                                │
│ FileOpen                              │    73 │ Number of files opened.                                                                                                                                                                                                                                    │
│ ReadBufferFromFileDescriptorRead      │   155 │ Number of reads (read/pread) from a file descriptor. Does not include sockets.                                                                                                                                                                             │
│ ReadBufferFromFileDescriptorReadBytes │  9931 │ Number of bytes read from file descriptors. If the file is compressed, this will show the compressed data size.                                                                                                                                              │
└───────────────────────────────────────┴───────┴────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘

Event descriptions

ACMEAPIRequests

Number of ACME API requests issued.

ACMECertificateOrders

Number of ACME certificate orders issued.

AIAPICalls

Number of HTTP requests dispatched to AI providers.

AIInputTokens

Total prompt tokens consumed across all AI function calls in the query.

AIORead

Number of reads with Linux or FreeBSD AIO interface

AIOReadBytes

Number of bytes read with Linux or FreeBSD AIO interface

AIOWrite

Number of writes with Linux or FreeBSD AIO interface

AIOWriteBytes

Number of bytes written with Linux or FreeBSD AIO interface

AIOutputTokens

Total completion tokens consumed across all AI function calls in the query.

AIRowsProcessed

Number of rows that received an AI result.

AIRowsSkipped

Number of rows that received a default value due to quota or error.

ASTFuzzerQueries

Number of fuzzed queries attempted by the server-side AST fuzzer.

AddressesDiscovered

Total count of new addresses in DNS resolve results for HTTP connections

AddressesExpired

Total count of expired addresses which is no longer presented in DNS resolve results for HTTP connections

AddressesMarkedAsFailed

Total count of addresses which have been marked as faulty due to connection errors for HTTP connections

AggregatingSortedMilliseconds

Total time spent while aggregating sorted columns

AggregationHashTablesInitializedAsTwoLevel

How many hash tables were inited as two-level for aggregation.

AggregationOptimizedEqualRangesOfKeys

For how many blocks optimization of equal ranges of keys was applied

AggregationPreallocatedElementsInHashTables

How many elements were preallocated in hash tables for aggregation.

AllUsersThrottlerBytes

Bytes passed through ‘max_network_bandwidth_for_all_users’ throttler.

AllUsersThrottlerSleepMicroseconds

Total time a query was sleeping to conform ‘max_network_bandwidth_for_all_users’ throttling.

AnalyzePatchRangesMicroseconds

Total time spent analyzing index of patch parts

ApplyPatchesMicroseconds

Total time spent applying patch parts to blocks

ArenaAllocBytes

Number of bytes allocated for memory Arena (used for GROUP BY and similar operations)

ArenaAllocChunks

Number of chunks allocated for memory Arena (used for GROUP BY and similar operations)

AsyncInsertBytes

Data size in bytes of asynchronous INSERT queries.

AsyncInsertCacheHits

Number of times a duplicate hash id has been found in asynchronous INSERT hash id cache.

AsyncInsertQuery

Same as InsertQuery, but only for asynchronous INSERT queries.

AsyncInsertRows

Number of rows inserted by asynchronous INSERT queries.

AsyncLoaderWaitMicroseconds

Total time a query was waiting for async loader jobs.

AsyncLoggingConsoleDroppedMessages

How many messages have been dropped from the console log due to the async log queue being full

AsyncLoggingConsoleTotalMessages

How many messages (accepted or dropped) have been sent to the async queue for the console log

AsyncLoggingErrorFileLogDroppedMessages

How many messages have been dropped from error file log due to the async log queue being full

AsyncLoggingErrorFileLogTotalMessages

How many messages (accepted or dropped) have been sent to the async queue for the error file log

AsyncLoggingFileLogDroppedMessages

How many messages have been dropped from the file log due to the async log queue being full

AsyncLoggingFileLogTotalMessages

How many messages (accepted or dropped) have been sent to the async queue for the file log

AsyncLoggingSyslogDroppedMessages

How many messages have been dropped from the syslog due to the async log queue being full

AsyncLoggingSyslogTotalMessages

How many messages (accepted or dropped) have been sent to the async queue for the syslog

AsyncLoggingTextLogDroppedMessages

How many messages have been dropped from text_log due to the async log queue being full

AsyncLoggingTextLogTotalMessages

How many messages (accepted or dropped) have been sent to the async queue for the text_log

AsynchronousReadWaitMicroseconds

Time spent in waiting for asynchronous reads in asynchronous local read.

AsynchronousReaderIgnoredBytes

Number of bytes ignored during asynchronous reading

AsynchronousRemoteReadWaitMicroseconds

Time spent in waiting for asynchronous remote reads.

AzureCommitBlockList

Number of Azure blob storage API CommitBlockList calls

AzureCopyObject

Number of Azure blob storage API CopyObject calls

AzureCreateContainer

Number of Azure blob storage API CreateContainer calls.

AzureDeleteObjects

Number of Azure blob storage API DeleteObject(s) calls.

AzureGetObject

Number of Azure API GetObject calls.

AzureGetProperties

Number of Azure blob storage API GetProperties calls.

AzureGetRequestThrottlerBlocked

Number of Azure GET requests blocked by throttler.

AzureGetRequestThrottlerCount

Number of Azure GET requests passed through throttler: blocked and not blocked.

AzureGetRequestThrottlerSleepMicroseconds

Total time a query was sleeping to conform Azure GET request throttling.

AzureListObjects

Number of Azure blob storage API ListObjects calls.

AzurePutRequestThrottlerBlocked

Number of Azure PUT requests blocked by throttler.

AzurePutRequestThrottlerCount

Number of Azure PUT requests passed through throttler: blocked and not blocked.

AzurePutRequestThrottlerSleepMicroseconds

Total time a query was sleeping to conform Azure PUT request throttling.

AzureReadMicroseconds

Total time spent waiting for Azure read requests.

AzureReadRequestsCount

Number of Azure read requests.

AzureReadRequestsErrors

Number of Azure read request errors.

AzureReadRequestsRedirects

Number of Azure read request redirects.

AzureReadRequestsThrottling

Number of Azure read requests throttled.

AzureStageBlock

Number of Azure blob storage API StageBlock calls

AzureUpload

Number of Azure blob storage API Upload calls

AzureWriteMicroseconds

Total time spent waiting for Azure write requests.

AzureWriteRequestsCount

Number of Azure write requests.

AzureWriteRequestsErrors

Number of Azure write request errors.

AzureWriteRequestsRedirects

Number of Azure write request redirects.

AzureWriteRequestsThrottling

Number of Azure write requests throttled.

BackgroundLoadingMarksTasks

Number of background tasks for loading marks

BackupEntriesCollectorForTablesDataMicroseconds

Time spent making backup entries for tables data

BackupEntriesCollectorMicroseconds

Time spent making backup entries

BackupEntriesCollectorRunPostTasksMicroseconds

Time spent running post tasks after making backup entries

BackupLockFileReads

How many times the ‘.lock’ file was read while making backup

BackupPreparingFileInfosMicroseconds

Time spent preparing file infos for backup entries

BackupReadLocalBytesToCalculateChecksums

Total size of files read locally to calculate checksums for backup entries

BackupReadLocalFilesToCalculateChecksums

Number of files read locally to calculate checksums for backup entries

BackupReadMetadataMicroseconds

Time spent reading backup metadata from .backup file

BackupReadRemoteBytesToCalculateChecksums

Total size of files read from remote disks to calculate checksums for backup entries

BackupReadRemoteFilesToCalculateChecksums

Number of files read from remote disks to calculate checksums for backup entries

BackupThrottlerBytes

Bytes passed through ‘max_backup_bandwidth_for_server’ throttler.

BackupThrottlerSleepMicroseconds

Total time a query was sleeping to conform ‘max_backup_bandwidth_for_server’ throttling.

BackupWriteMetadataMicroseconds

Time spent writing backup metadata to .backup file

BackupsOpenedForRead

Number of backups opened for reading

BackupsOpenedForUnlock

Number of backups opened for unlocking

BackupsOpenedForWrite

Number of backups opened for writing

BlobCopierThreadLockBlobsErrors

Number of blobs lock errors occurred during BlobCopier execution

BlobCopierThreadLockedBlobs

Number of blobs returned from metadata storage

BlobCopierThreadRecordBlobsErrors

Number of blobs recording errors occurred during BlobCopier execution

BlobCopierThreadRecordedBlobs

Number of blobs which replication by BlobCopier was recorded in metadata storage

BlobCopierThreadReplicateBlobsErrors

Number of blobs replication errors occurred during BlobCopier execution

BlobCopierThreadReplicatedBlobs

Number of blobs replicated by BlobCopier

BlobCopierThreadRuns

Number of BlobCopier thread executes

BlobKillerThreadLockBlobsErrors

Number of blobs lock errors occurred during BlobKiller execution

BlobKillerThreadLockedBlobs

Number of blobs returned from metadata storage

BlobKillerThreadRecordBlobsErrors

Number of blobs recording errors occurred during BlobKiller execution

BlobKillerThreadRecordedBlobs

Number of blobs which removal by BlobKiller was recorded in metadata storage

BlobKillerThreadRemoveBlobsErrors

Number of blobs removal errors occurred during BlobKiller execution

BlobKillerThreadRemoveTasks

Number of remove tasks created by BlobKiller

BlobKillerThreadRemovedBlobs

Number of blobs removed by BlobKiller

BlobKillerThreadRuns

Number of BlobKiller thread executes

BuildPatchesJoinMicroseconds

Total time spent building indexes and hash tables for applying patch parts with Join mode

BuildPatchesMergeMicroseconds

Total time spent building indexes for applying patch parts with Merge mode

CacheWarmerBytesDownloaded

Amount of data fetched into filesystem cache by dedicated background threads.

CacheWarmerDataPartsDownloaded

Number of data parts that were fully fetched by CacheWarmer.

CachedReadBufferCacheWriteBytes

Bytes written from source (remote fs, etc) to filesystem cache

CachedReadBufferCacheWriteMicroseconds

Time spent writing data into filesystem cache

CachedReadBufferCreateBufferMicroseconds

Prepare buffer time

CachedReadBufferPredownloadedBytes

Bytes read from filesystem cache source. Cache segments are read from left to right as a whole, it might be that we need to predownload some part of the segment irrelevant for the current task just to get to the needed data

CachedReadBufferPredownloadedFromSourceBytes

Bytes read from filesystem cache source for predownload (from remote fs, etc)

CachedReadBufferPredownloadedFromSourceMicroseconds

Time reading from filesystem cache source for predownload (from remote filesystem, etc)

CachedReadBufferReadFromCacheBytes

Bytes read from filesystem cache

CachedReadBufferReadFromCacheHits

Number of times the read from filesystem cache hit the cache.

CachedReadBufferReadFromCacheMicroseconds

Time reading from filesystem cache

CachedReadBufferReadFromCacheMisses

Number of times the read from filesystem cache miss the cache.

CachedReadBufferReadFromSourceBytes

Bytes read from filesystem cache source (from remote fs, etc)

CachedReadBufferReadFromSourceMicroseconds

Time reading from filesystem cache source (from remote filesystem, etc)

CachedReadBufferWaitReadBufferMicroseconds

Time spend waiting for internal read buffer (includes cache waiting)

CachedWriteBufferCacheWriteBytes

Bytes written from source (remote fs, etc) to filesystem cache

CachedWriteBufferCacheWriteMicroseconds

Time spent writing data into filesystem cache

CannotRemoveEphemeralNode

Number of times an error happened while trying to remove ephemeral node. This is not an issue, because our implementation of ZooKeeper library guarantee that the session will expire and the node will be removed.

CannotWriteToWriteBufferDiscard

Number of stack traces dropped by query profiler or signal handler because pipe is full or cannot write to pipe.

CoalescingSortedMilliseconds

Total time spent while coalescing sorted columns

CollapsingSortedMilliseconds

Total time spent while collapsing sorted columns

CommonBackgroundExecutorTaskCancelMicroseconds

Time spent in cancel() for Common executor tasks.

CommonBackgroundExecutorTaskExecuteStepMicroseconds

Time spent in executeStep() for Common executor tasks.

CommonBackgroundExecutorTaskResetMicroseconds

Time spent resetting task for Common executor.

CommonBackgroundExecutorWaitMicroseconds

Time spent waiting for completion in Common executor.

CompileExpressionsBytes

Number of bytes used for expressions compilation.

CompileExpressionsMicroseconds

Total time spent for compilation of expressions to LLVM code.

CompileFunction

Number of times a compilation of generated LLVM code (to create fused function for complex expressions) was initiated.

CompiledFunctionExecute

Number of times a compiled function was executed.

CompressedReadBufferBlocks

Number of compressed blocks (the blocks of data that are compressed independent of each other) read from compressed sources (files, network).

CompressedReadBufferBytes

Number of uncompressed bytes (the number of bytes after decompression) read from compressed sources (files, network).

CompressedReadBufferChecksumDoesntMatch

Number of times the compressed block checksum did not match.

CompressedReadBufferChecksumDoesntMatchMicroseconds

Total time spent detecting bit-flips due to compressed block checksum mismatches.

CompressedReadBufferChecksumDoesntMatchSingleBitMismatch

Number of times a compressed block checksum mismatch was caused by a single-bit difference.

ConcurrencyControlDownscales

Total number of CPU downscaling events

ConcurrencyControlPreemptedMicroseconds

Total time a query was waiting due to preemption of CPU slots.

ConcurrencyControlPreemptions

Total number of CPU preemptions

ConcurrencyControlQueriesDelayed

Total number of CPU slot allocations (queries) that were required to wait for slots to upscale

ConcurrencyControlSlotsAcquired

Total number of CPU slots acquired

ConcurrencyControlSlotsAcquiredNonCompeting

Total number of noncompeting CPU slot acquired

ConcurrencyControlSlotsDelayed

Number of CPU slot not granted initially and required to wait for a free CPU slot

ConcurrencyControlSlotsGranted

Number of CPU slot granted according to guarantee of 1 thread per query and for queries with setting ‘use_concurrency_control’ = 0

ConcurrencyControlUpscales

Total number of CPU upscaling events

ConcurrencyControlWaitMicroseconds

Total time a query was waiting on resource requests for CPU slots.

ConcurrentQuerySlotsAcquired

Total number of query slots acquired

ConcurrentQueryWaitMicroseconds

Total time a query was waiting for a query slots

ConnectionPoolIsFullMicroseconds

Total time spent waiting for a slot in connection pool.

ContextLock

Number of times the lock of Context was acquired or tried to acquire. This is global lock.

ContextLockWaitMicroseconds

Context lock wait time in microseconds

CoordinatedMergesMergeAssignmentRequest

Total number of merge assignment requests

CoordinatedMergesMergeAssignmentRequestMicroseconds

Total time spend in merge assignment client

CoordinatedMergesMergeAssignmentResponse

Total number of merge assignment requests

CoordinatedMergesMergeAssignmentResponseMicroseconds

Total time spend in merge assignment handler

CoordinatedMergesMergeCoordinatorFetchMetadataMicroseconds

Total time spend on fetching fresh metadata inside merge coordinator

CoordinatedMergesMergeCoordinatorFilterMicroseconds

Total time spend on filtering prepared merges inside merge coordinator

CoordinatedMergesMergeCoordinatorLockStateExclusivelyCount

Total number of exclusive captures of coordinator state lock

CoordinatedMergesMergeCoordinatorLockStateExclusivelyMicroseconds

Total time spend on locking coordinator state mutex exclusively

CoordinatedMergesMergeCoordinatorLockStateForShareCount

Total number of for share captures of coordinator state lock

CoordinatedMergesMergeCoordinatorLockStateForShareMicroseconds

Total time spend on locking coordinator state mutex for share

CoordinatedMergesMergeCoordinatorSelectMergesMicroseconds

Total time spend on finding merge using merge selectors inside merge coordinator

CoordinatedMergesMergeCoordinatorUpdateCount

Total number of merge coordinator updates

CoordinatedMergesMergeCoordinatorUpdateMicroseconds

Total time spend on updating merge coordinator state

CoordinatedMergesMergeWorkerUpdateCount

Total number merge worker updates

CoordinatedMergesMergeWorkerUpdateMicroseconds

Total time spend on updating local state of assigned merges on worker

CreatedLogEntryForMerge

Successfully created log entry to merge parts in ReplicatedMergeTree.

CreatedLogEntryForMutation

Successfully created log entry to mutate parts in ReplicatedMergeTree.

CreatedReadBufferDirectIO

Number of times a read buffer with O_DIRECT was created for reading data (while choosing among other read methods).

CreatedReadBufferDirectIOFailed

Number of times a read buffer with O_DIRECT was attempted to be created for reading data (while choosing among other read methods), but the OS did not allow it (due to lack of filesystem support or other reasons) and we fallen back to the ordinary reading method.

CreatedReadBufferMMap

Number of times a read buffer using ‘mmap’ was created for reading data (while choosing among other read methods).

CreatedReadBufferMMapFailed

Number of times a read buffer with ‘mmap’ was attempted to be created for reading data (while choosing among other read methods), but the OS did not allow it (due to lack of filesystem support or other reasons) and we fallen back to the ordinary reading method.

CreatedReadBufferOrdinary

Number of times ordinary read buffer was created for reading data (while choosing among other read methods).

DNSError

Total count of errors in DNS resolution

DataAfterMergeDiffersFromReplica

Number of times data after merge is not byte-identical to the data on another replicas. There could be several reasons:

Using newer version of compression library after server update.
Using another compression method.
Non-deterministic compression algorithm (highly unlikely).
Non-deterministic merge algorithm due to logical error in code.
Data corruption in memory due to bug in code.
Data corruption in memory due to hardware issue.
Manual modification of source data after server startup.
Manual modification of checksums stored in ZooKeeper.
Part format related settings like ‘enable_mixed_granularity_parts’ are different on different replicas. The server successfully detected this situation and will download merged part from the replica to force the byte-identical result.

DataAfterMutationDiffersFromReplica

Number of times data after mutation is not byte-identical to the data on other replicas. In addition to the reasons described in ‘DataAfterMergeDiffersFromReplica’, it is also possible due to non-deterministic mutation.

DefaultImplementationForNullsRows

Number of rows processed by default implementation for nulls in function execution

DefaultImplementationForNullsRowsWithNulls

Number of rows which contain null values processed by default implementation for nulls in function execution

DelayedInserts

Number of times the INSERT of a block to a MergeTree table was throttled due to high number of active data parts for partition.

DelayedInsertsMilliseconds

Total number of milliseconds spent while the INSERT of a block to a MergeTree table was throttled due to high number of active data parts for partition.

DelayedMutations

Number of times the mutation of a MergeTree table was throttled due to high number of unfinished mutations for table.

DelayedMutationsMilliseconds

Total number of milliseconds spent while the mutation of a MergeTree table was throttled due to high number of unfinished mutations for table.

DeltaLakePartitionPrunedFiles

Number of skipped files during DeltaLake partition pruning

DeltaLakeScannedFiles

Number of files scanned during DeltaLake scan callbacks

DeltaLakeSnapshotInitializations

Number of times a DeltaLake table snapshot was initialized (loaded from object storage)

DictCacheKeysExpired

Number of keys looked up in the dictionaries of ‘cache’ types and found in the cache but they were obsolete.

DictCacheKeysHit

Number of keys looked up in the dictionaries of ‘cache’ types and found in the cache.

DictCacheKeysNotFound

Number of keys looked up in the dictionaries of ‘cache’ types and not found.

DictCacheKeysRequested

Number of keys requested from the data source for the dictionaries of ‘cache’ types.

DictCacheKeysRequestedFound

Number of keys requested from the data source for dictionaries of ‘cache’ types and found in the data source.

DictCacheKeysRequestedMiss

Number of keys requested from the data source for dictionaries of ‘cache’ types but not found in the data source.

DictCacheLockReadNs

Number of nanoseconds spend in waiting for read lock to lookup the data for the dictionaries of ‘cache’ types.

DictCacheLockWriteNs

Number of nanoseconds spend in waiting for write lock to update the data for the dictionaries of ‘cache’ types.

DictCacheRequestTimeNs

Number of nanoseconds spend in querying the external data sources for the dictionaries of ‘cache’ types.

DictCacheRequests

Number of bulk requests to the external data sources for the dictionaries of ‘cache’ types.

DirectorySync

Number of times the F_FULLFSYNC/fsync/fdatasync function was called for directories.

DirectorySyncElapsedMicroseconds

Total time spent waiting for F_FULLFSYNC/fsync/fdatasync syscall for directories.

DiskAzureCommitBlockList

Number of Disk Azure blob storage API CommitBlockList calls

DiskAzureCopyObject

Number of Disk Azure blob storage API CopyObject calls

DiskAzureCreateContainer

Number of Disk Azure blob storage API CreateContainer calls.

DiskAzureDeleteObjects

Number of Azure blob storage API DeleteObject(s) calls.

DiskAzureGetObject

Number of Disk Azure API GetObject calls.

DiskAzureGetProperties

Number of Disk Azure blob storage API GetProperties calls.

DiskAzureGetRequestThrottlerBlocked

Number of Azure disk GET requests blocked by throttler.

DiskAzureGetRequestThrottlerCount

Number of Azure disk GET requests passed through throttler: blocked and not blocked.

DiskAzureGetRequestThrottlerSleepMicroseconds

Total time a query was sleeping to conform Azure disk GET request throttling.

DiskAzureListObjects

Number of Disk Azure blob storage API ListObjects calls.

DiskAzurePutRequestThrottlerBlocked

Number of Azure disk PUT requests blocked by throttler.

DiskAzurePutRequestThrottlerCount

Number of Azure disk PUT requests passed through throttler: blocked and not blocked.

DiskAzurePutRequestThrottlerSleepMicroseconds

Total time a query was sleeping to conform Azure disk PUT request throttling.

DiskAzureReadMicroseconds

Total time spent waiting for Azure disk read requests.

DiskAzureReadRequestsCount

Number of Azure disk read requests.

DiskAzureReadRequestsErrors

Number of Azure disk read request errors.

DiskAzureReadRequestsRedirects

Number of Azure disk read request redirects.

DiskAzureReadRequestsThrottling

Number of Azure disk read requests throttled.

DiskAzureStageBlock

Number of Disk Azure blob storage API StageBlock calls

DiskAzureUpload

Number of Disk Azure blob storage API Upload calls

DiskAzureWriteMicroseconds

Total time spent waiting for Azure disk write requests.

DiskAzureWriteRequestsCount

Number of Azure disk write requests.

DiskAzureWriteRequestsErrors

Number of Azure disk write request errors.

DiskAzureWriteRequestsRedirects

Number of Azure disk write request redirects.

DiskAzureWriteRequestsThrottling

Number of Azure disk write requests throttled.

DiskConnectionsCreated

Number of created connections for disk

DiskConnectionsElapsedMicroseconds

Total time spend on creating connections for disk

DiskConnectionsErrors

Number of cases when creation of a connection for disk is failed

DiskConnectionsExpired

Number of expired connections for disk

DiskConnectionsPreserved

Number of preserved connections for disk

DiskConnectionsReset

Number of reset connections for disk

DiskConnectionsReused

Number of reused connections for disk

DiskObjectStorageWaitBlobRemovalMicroseconds

Time spent waiting for pending blob removal after committing metadata transaction

DiskPlainRewritableAzureDirectoryCreated

Number of directories created by the ‘plain_rewritable’ metadata storage for AzureObjectStorage.

DiskPlainRewritableAzureDirectoryRemoved

Number of directories removed by the ‘plain_rewritable’ metadata storage for AzureObjectStorage.

DiskPlainRewritableLegacyLayoutDiskCount

Number of the ‘plain_rewritable’ disks with legacy layout.

DiskPlainRewritableLocalDirectoryCreated

Number of directories created by the ‘plain_rewritable’ metadata storage for LocalObjectStorage.

DiskPlainRewritableLocalDirectoryRemoved

Number of directories removed by the ‘plain_rewritable’ metadata storage for LocalObjectStorage.

DiskPlainRewritableS3DirectoryCreated

Number of directories created by the ‘plain_rewritable’ metadata storage for S3ObjectStorage.

DiskPlainRewritableS3DirectoryRemoved

Number of directories removed by the ‘plain_rewritable’ metadata storage for S3ObjectStorage.

DiskReadElapsedMicroseconds

Total time spent waiting for read syscall. This include reads from page cache.

DiskS3AbortMultipartUpload

Number of DiskS3 API AbortMultipartUpload calls.

DiskS3CompleteMultipartUpload

Number of DiskS3 API CompleteMultipartUpload calls.

DiskS3CopyObject

Number of DiskS3 API CopyObject calls.

DiskS3CreateMultipartUpload

Number of DiskS3 API CreateMultipartUpload calls.

DiskS3DeleteObjects

Number of DiskS3 API DeleteObject(s) calls.

DiskS3GetObject

Number of DiskS3 API GetObject calls.

DiskS3GetObjectTagging

Number of DiskS3 API GetObjectTagging calls.

DiskS3GetRequestThrottlerBlocked

Number of DiskS3 GET and SELECT requests blocked by throttler.

DiskS3GetRequestThrottlerCount

Number of DiskS3 GET and SELECT requests passed through throttler: blocked and not blocked.

DiskS3GetRequestThrottlerSleepMicroseconds

Total time a query was sleeping to conform DiskS3 GET and SELECT request throttling.

DiskS3HeadObject

Number of DiskS3 API HeadObject calls.

DiskS3ListObjects

Number of DiskS3 API ListObjects calls.

DiskS3PutObject

Number of DiskS3 API PutObject calls.

DiskS3PutRequestThrottlerBlocked

Number of DiskS3 PUT, COPY, POST and LIST requests blocked by throttler.

DiskS3PutRequestThrottlerCount

Number of DiskS3 PUT, COPY, POST and LIST requests passed through throttler: blocked and not blocked.

DiskS3PutRequestThrottlerSleepMicroseconds

Total time a query was sleeping to conform DiskS3 PUT, COPY, POST and LIST request throttling.

DiskS3ReadMicroseconds

Time of GET and HEAD requests to DiskS3 storage.

DiskS3ReadRequestAttempts

Number of attempts for GET and HEAD requests to DiskS3 storage, including the initial try and any retries, but excluding retries performed internally by the S3 retry strategy

DiskS3ReadRequestRetryableErrors

Number of retryable errors for GET and HEAD requests to DiskS3 storage, excluding retries performed internally by the S3 retry strategy

DiskS3ReadRequestsCount

Number of GET and HEAD requests to DiskS3 storage.

DiskS3ReadRequestsErrors

Number of non-throttling errors in GET and HEAD requests to DiskS3 storage.

DiskS3ReadRequestsRedirects

Number of redirects in GET and HEAD requests to DiskS3 storage.

DiskS3ReadRequestsThrottling

Number of 429 and 503 errors in GET and HEAD requests to DiskS3 storage.

DiskS3UploadPart

Number of DiskS3 API UploadPart calls.

DiskS3UploadPartCopy

Number of DiskS3 API UploadPartCopy calls.

DiskS3WriteMicroseconds

Time of POST, DELETE, PUT and PATCH requests to DiskS3 storage.

DiskS3WriteRequestAttempts

Number of attempts for POST, DELETE, PUT and PATCH requests to DiskS3 storage, including the initial try and any retries, but excluding retries performed internally by the retry strategy

DiskS3WriteRequestRetryableErrors

Number of retryable errors for POST, DELETE, PUT and PATCH requests to DiskS3 storage, excluding retries performed internally by the retry strategy

DiskS3WriteRequestsCount

Number of POST, DELETE, PUT and PATCH requests to DiskS3 storage.

DiskS3WriteRequestsErrors

Number of non-throttling errors in POST, DELETE, PUT and PATCH requests to DiskS3 storage.

DiskS3WriteRequestsRedirects

Number of redirects in POST, DELETE, PUT and PATCH requests to DiskS3 storage.

DiskS3WriteRequestsThrottling

Number of 429 and 503 errors in POST, DELETE, PUT and PATCH requests to DiskS3 storage.

DiskWriteElapsedMicroseconds

Total time spent waiting for write syscall. This include writes to page cache.

DistrCacheConnectAttempts

Distributed Cache connection event. The number of connection attempts to distributed cache

DistrCacheConnectMicroseconds

Distributed Cache connection event. The time spent to connect to distributed cache

DistrCacheFallbackReadMicroseconds

Distributed Cache read buffer event. Time spend reading from fallback buffer instead of distributed cache

DistrCacheGetClientMicroseconds

Distributed Cache connection event. Time spent getting client for distributed cache

DistrCacheGetResponseMicroseconds

Distributed Cache client event. Time spend to wait for response from distributed cache

DistrCacheHashRingRebuilds

Distributed Cache registry event. Number of distributed cache hash ring rebuilds

DistrCacheLockRegistryMicroseconds

Distributed Cache registry event. Time spent to take DistributedCacheRegistry lock

DistrCacheMakeRequestErrors

Distributed Cache client event. Number of distributed cache errors when making a request

DistrCacheNextImplMicroseconds

Distributed Cache read buffer event. Time spend in ReadBufferFromDistributedCache::nextImpl

DistrCacheObjectStorageWriteBytes

Distributed Cache write buffer event. Number of bytes written to object storage

DistrCacheObjectStorageWriteMicroseconds

Distributed Cache write buffer event. Time spent writing to object storage

DistrCacheOpenedConnections

Distributed Cache connection event. The number of open connections to distributed cache

DistrCacheOpenedConnectionsBypassingPool

Distributed Cache connection event. The number of open connections to distributed cache bypassing pool

DistrCachePrecomputeRangesMicroseconds

Distributed Cache read buffer event. Time spent to precompute read ranges

DistrCacheRangeChange

Distributed Cache read buffer event. Number of times we changed read range because of seek/last_position change

DistrCacheRangeResetBackward

Distributed Cache read buffer event. Number of times we reset read range because of seek/last_position change

DistrCacheRangeResetForward

Distributed Cache read buffer event. Number of times we reset read range because of seek/last_position change

DistrCacheReadBytesFromFallbackBuffer

Distributed Cache read buffer event. Bytes read from fallback buffer

DistrCacheReadErrors

Distributed Cache read buffer event. Number of distributed cache errors during read

DistrCacheReadMicroseconds

Distributed Cache read buffer event. Time spent reading from distributed cache

DistrCacheReadThrottlerBytes

Bytes passed through ‘max_distributed_cache_read_bandwidth_for_server’ throttler.

DistrCacheReadThrottlerSleepMicroseconds

Total time a query was sleeping to conform ‘max_distributed_cache_read_bandwidth_for_server’ throttling.

DistrCacheReceiveResponseErrors

Distributed Cache client event. Number of distributed cache errors when receiving response a request

DistrCacheReceivedCredentialsRefreshPackets

Distributed Cache client event. Total number of received RefreshCredentials packets received from distributed cache

DistrCacheReceivedDataPackets

Distributed Cache client event. Total number of received data packets received from distributed cache

DistrCacheReceivedDataPacketsBytes

Distributed Cache client event. The number of bytes in Data packets received from distributed cache

DistrCacheReceivedErrorPackets

Distributed Cache client event. Total number of received Error packets received from distributed cache

DistrCacheReceivedOkPackets

Distributed Cache client event. Total number of received Ok packets received from distributed cache

DistrCacheReceivedStopPackets

Distributed Cache client event. Total number of received Stop packets received from distributed cache

DistrCacheReconnectsAfterTimeout

Distributed Cache read buffer event. The number of reconnects after timeout

DistrCacheRegistryUpdateMicroseconds

Distributed Cache registry event. Time spent updating distributed cache registry

DistrCacheRegistryUpdates

Distributed Cache registry event. Number of distributed cache registry updates

DistrCacheRemoveOutdatedMicroseconds

Distributed Cache connection event. The time spent removing outdated connections from the pool

DistrCacheReusedConnections

Distributed Cache connection event. The number of reused connections to distributed cache

DistrCacheSentDataPackets

Distributed Cache client event. Total number of data packets sent to distributed cache

DistrCacheSentDataPacketsBytes

Distributed Cache client event. The number of bytes in Data packets sent to distributed cache

DistrCacheServerAckRequestPackets

Distributed Cache server event. Number of AckRequest packets in DistributedCacheServer

DistrCacheServerCachedReadBufferCacheHits

Distributed Cache server event. The number of times distributed cache hit the cache while reading from filesystem cache

DistrCacheServerCachedReadBufferCacheMisses

Distributed Cache server event. The number of times distributed cache missed the cache while reading from filesystem cache

DistrCacheServerCachedReadBufferCachePredownloadBytes

Distributed Cache server event. The number of bytes read from object storage for predownload in distributed cache while reading from filesystem cache

DistrCacheServerCachedReadBufferCacheReadBytes

Distributed Cache server event. The number of bytes read from cache in distributed cache while reading from filesystem cache

DistrCacheServerCachedReadBufferCacheWrittenBytes

Distributed Cache server event. The number of bytes written to cache in distributed cache while reading from filesystem cache

DistrCacheServerCachedReadBufferObjectStorageReadBytes

Distributed Cache server event. The number of bytes read from object storage in distributed cache while reading from filesystem cache

DistrCacheServerContinueRequestPackets

Distributed Cache server event. Number of ContinueRequest packets in DistributedCacheServer

DistrCacheServerCredentialsRefresh

Distributed Cache server event. The number of expired credentials were refreshed

DistrCacheServerEndRequestPackets

Distributed Cache server event. Number of EndRequest packets in DistributedCacheServer

DistrCacheServerNewS3CachedClients

Distributed Cache server event. The number of new cached s3 clients

DistrCacheServerProcessRequestMicroseconds

Distributed Cache server event. Time spent processing request on DistributedCache server side

DistrCacheServerReceivedCredentialsRefreshPackets

Distributed Cache server event. Number of RefreshCredentials client packets in DistributedCacheServer

DistrCacheServerReusedS3CachedClients

Distributed Cache server event. The number of reused cached s3 clients

DistrCacheServerSkipped

Distributed Cache server event. The number of times distributed cache server was skipped because of previous failed connection attempts

DistrCacheServerStartRequestPackets

Distributed Cache server event. Number of StartRequest packets in DistributedCacheServer

DistrCacheServerSwitches

Distributed Cache read buffer event. Number of server switches between distributed cache servers in read/write-through cache

DistrCacheServerUpdates

Distributed Cache event. The number of server switches during read or write because the hash-chosen server changed (e.g. due to server deregistration)

DistrCacheStaleReconnections

Distributed Cache connection event. The number of reconnections due to stale (peer-closed) pooled connections

DistrCacheStartRangeMicroseconds

Distributed Cache read buffer event. Time spent to start a new read range with distributed cache

DistrCacheSuccessfulConnectAttempts

Distributed Cache connection event. The number of successful connection attempts to distributed cache

DistrCacheSuccessfulRegistryUpdates

Distributed Cache registry event. The number of successful server registry updates

DistrCacheTemporaryFilesBytesWritten

Distributed Cache connection event. Number of bytes written to temporary files created in distributed cache

DistrCacheTemporaryFilesCreated

Distributed Cache connection event. Number of temporary files created in distributed cache

DistrCacheUnsuccessfulConnectAttempts

Distributed Cache connection event. The number of unsuccessful connection attempts to distributed cache

DistrCacheUnsuccessfulRegistryUpdates

Distributed Cache registry event. The number of unsuccessful server registry updates

DistrCacheUnusedDataPacketsBytes

Distributed Cache client event. The number of bytes in Data packets which were ignored

DistrCacheUnusedPackets

Distributed Cache client event. Number of skipped unused packets from distributed cache

DistrCacheUnusedPacketsBufferAllocations

Distributed Cache client event. The number of extra buffer allocations in case we could not reuse existing buffer

DistrCacheWriteBytes

Distributed Cache write buffer event. Number of bytes written to distributed cache

DistrCacheWriteErrors

Distributed Cache write buffer event. Number of distributed cache errors during write

DistrCacheWriteMicroseconds

Distributed Cache write buffer event. Time spent in WriteBufferFromDistributedCache::writeToFileSegment

DistrCacheWriteReconnectsAfterTimeout

Distributed Cache write buffer event. The number of reconnects after timeout

DistrCacheWriteThrottlerBytes

Bytes passed through ‘max_distributed_cache_write_bandwidth_for_server’ throttler.

DistrCacheWriteThrottlerSleepMicroseconds

Total time a query was sleeping to conform ‘max_distributed_cache_write_bandwidth_for_server’ throttling.

DistributedAsyncInsertionFailures

Number of failures for asynchronous insertion into a Distributed table (with ‘distributed_foreground_insert’ = 0)

DistributedConnectionConnectCount

Number of connects to other servers done during distributed query execution. Happens when new connection is established instead of using existing from pool.

DistributedConnectionFailAtAll

Total count when distributed connection fails after all retries finished.

DistributedConnectionFailTry

Total count when distributed connection fails with retry.

DistributedConnectionMissingTable

Number of times we rejected a replica from a distributed query, because it did not contain a table needed for the query.

DistributedConnectionReconnectCount

Number of reconnects to other servers done during distributed query execution. It can happen when a stale connection has been acquired from connection pool

DistributedConnectionSkipReadOnlyReplica

Number of replicas skipped during INSERT into Distributed table due to replicas being read-only

DistributedConnectionStaleReplica

Number of times we rejected a replica from a distributed query, because some table needed for a query had replication lag higher than the configured threshold.

DistributedConnectionTries

Total count of distributed connection attempts.

DistributedConnectionUsable

Total count of successful distributed connections to a usable server (with required table, but maybe stale).

DistributedDelayedInserts

Number of times the INSERT of a block to a Distributed table was throttled due to high number of pending bytes.

DistributedDelayedInsertsMilliseconds

Total number of milliseconds spent while the INSERT of a block to a Distributed table was throttled due to high number of pending bytes.

DistributedIndexAnalysisMicroseconds

Total time spent during distributed index analysis

DistributedIndexAnalysisMissingParts

Number of missing parts during distributed index analysis that will be resolved locally

DistributedIndexAnalysisParts

Number of parts send for distributed index analysis

DistributedIndexAnalysisReplicaFallback

Number of times distributed index analysis failed on one of replicas with fallback to local replica

DistributedIndexAnalysisReplicaUnavailable

Number of times distributed index analysis failed on one of replicas without fallback (failed during connect)

DistributedIndexAnalysisScheduledReplicas

Number of replicas (local replica will be accounted once) to which distributed index analysis has been scheduled

DistributedRejectedInserts

Number of times the INSERT of a block to a Distributed table was rejected with ‘Too many bytes’ exception due to high number of pending bytes.

DistributedSyncInsertionTimeoutExceeded

A timeout has exceeded while waiting for shards during synchronous insertion into a Distributed table (with ‘distributed_foreground_insert’ = 1)

DuplicatedAsyncInserts

Number of async inserts in the INSERTed block to a ReplicatedMergeTree table was deduplicated.

DuplicatedInsertedBlocks

Number of the synchronous inserts to a *MergeTree table was deduplicated.

DuplicationElapsedMicroseconds

Total time spent checking for duplication of INSERTed blocks to *MergeTree tables.

EngineFileLikeReadFiles

Number of files read in table engines working with files (like File/S3/URL/HDFS).

ExecuteShellCommand

Number of shell command executions.

ExternalAggregationCompressedBytes

Number of bytes written to disk for aggregation in external memory.

ExternalAggregationMerge

Number of times temporary files were merged for aggregation in external memory.

ExternalAggregationUncompressedBytes

Amount of data (uncompressed, before compression) written to disk for aggregation in external memory.

ExternalAggregationWritePart

Number of times a temporary file was written to disk for aggregation in external memory.

ExternalDataSourceLocalCacheReadBytes

Bytes read from local cache buffer in RemoteReadBufferCache

ExternalJoinCompressedBytes

Number of compressed bytes written for JOIN in external memory.

ExternalJoinMerge

Number of times temporary files were merged for JOIN in external memory.

ExternalJoinUncompressedBytes

Amount of data (uncompressed, before compression) written for JOIN in external memory.

ExternalJoinWritePart

Number of times a temporary file was written to disk for JOIN in external memory.

ExternalProcessingCompressedBytesTotal

Number of compressed bytes written by external processing (sorting/aggragating/joining)

ExternalProcessingFilesTotal

Number of files used by external processing (sorting/aggragating/joining)

ExternalProcessingUncompressedBytesTotal

Amount of data (uncompressed, before compression) written by external processing (sorting/aggragating/joining)

ExternalSortCompressedBytes

Number of compressed bytes written for sorting in external memory.

ExternalSortMerge

Number of times temporary files were merged for sorting in external memory.

ExternalSortUncompressedBytes

Amount of data (uncompressed, before compression) written for sorting in external memory.

ExternalSortWritePart

Number of times a temporary file was written to disk for sorting in external memory.

FailedAsyncInsertQuery

Number of failed ASYNC INSERT queries.

FailedInitialQuery

Number of failed initial queries.

FailedInitialSelectQuery

Same as FailedInitialQuery, but only for SELECT queries.

FailedInsertQuery

Same as FailedQuery, but only for INSERT queries.

FailedInternalInsertQuery

Same as FailedInternalQuery, but only for INSERT queries.

FailedInternalQuery

Number of failed internal queries.

FailedInternalSelectQuery

Same as FailedInternalQuery, but only for SELECT queries.

FailedQuery

Number of total failed queries, both internal and user queries.

FailedSelectQuery

Same as FailedQuery, but only for SELECT queries.

FetchBackgroundExecutorTaskCancelMicroseconds

Time spent in cancel() for Fetch executor tasks.

FetchBackgroundExecutorTaskExecuteStepMicroseconds

Time spent in executeStep() for Fetch executor tasks.

FetchBackgroundExecutorTaskResetMicroseconds

Time spent resetting task for Fetch executor.

FetchBackgroundExecutorWaitMicroseconds

Time spent waiting for completion in Fetch executor.

FileOpen

Number of files opened.

FileSegmentCompleteMicroseconds

Duration of FileSegment::complete() in filesystem cache

FileSegmentFailToIncreasePriority

Number of times the priority was not increased due to a high contention on the cache lock

FileSegmentHolderCompleteMicroseconds

File segments holder complete() time

FileSegmentIncreasePriorityMicroseconds

File segment increase priority time

FileSegmentLockMicroseconds

Lock file segment time

FileSegmentRemoveMicroseconds

File segment remove() time

FileSegmentWaitMicroseconds

Wait on DOWNLOADING state

FileSegmentWriteMicroseconds

File segment write() time

FileSync

Number of times the F_FULLFSYNC/fsync/fdatasync function was called for files.

FileSyncElapsedMicroseconds

Total time spent waiting for F_FULLFSYNC/fsync/fdatasync syscall for files.

FilesystemCacheBackgroundDownloadQueuePush

Number of file segments sent for background download in filesystem cache

FilesystemCacheBackgroundEvictedBytes

Number of bytes evicted by background thread

FilesystemCacheBackgroundEvictedFileSegments

Number of file segments evicted by background thread

FilesystemCacheCheckCorrectness

Number of times FileCache::assertCacheCorrectness was called

FilesystemCacheCheckCorrectnessMicroseconds

How much time does FileCache::assertCacheCorrectness takes

FilesystemCacheCreatedKeyDirectories

Number of created key directories

FilesystemCacheEvictMicroseconds

Filesystem cache eviction time

FilesystemCacheEvictedBytes

Number of bytes evicted from filesystem cache

FilesystemCacheEvictedFileSegments

Number of file segments evicted from filesystem cache

FilesystemCacheEvictedFileSegmentsDuringPriorityIncrease

Number of file segments evicted from filesystem cache when increasing priority of file segments (Applies to SLRU cache policy)

FilesystemCacheEvictionReusedIterator

Number of filesystem cache iterator reusing

FilesystemCacheEvictionSkippedEvictingFileSegments

Number of file segments skipped for eviction because of being in evicting state

FilesystemCacheEvictionSkippedFileSegments

Number of file segments skipped for eviction because of being in unreleasable state

FilesystemCacheEvictionSkippedMovingFileSegments

Number of file segments skipped for eviction because of being in moving state

FilesystemCacheEvictionTries

Number of filesystem cache eviction attempts

FilesystemCacheFailToReserveSpaceBecauseOfCacheResize

Number of times space reservation was skipped due to the cache is being resized

FilesystemCacheFailToReserveSpaceBecauseOfLockContention

Number of times space reservation was skipped due to a high contention on the cache lock

FilesystemCacheFailedEvictionCandidates

Number of file segments which unexpectedly failed to be evicted during dynamic filesystem cache eviction

FilesystemCacheFreeSpaceKeepingThreadRun

Number of times background thread executed free space keeping job

FilesystemCacheFreeSpaceKeepingThreadWorkMilliseconds

Time for which background thread executed free space keeping job

FilesystemCacheGetMicroseconds

Filesystem cache get() time

FilesystemCacheGetOrSetMicroseconds

Filesystem cache getOrSet() time

FilesystemCacheHoldFileSegments

Filesystem cache file segments count, which were hold

FilesystemCacheLoadMetadataMicroseconds

Time spent loading filesystem cache metadata

FilesystemCacheLockKeyMicroseconds

Lock cache key time

FilesystemCacheLockMetadataMicroseconds

Lock filesystem cache metadata time

FilesystemCachePriorityReadLockMicroseconds

Lock filesystem cache time for read in priority queue

FilesystemCachePriorityWriteLockMicroseconds

Lock filesystem cache time for write to priority queue

FilesystemCacheReserveAttempts

Filesystem cache space reservation attempt

FilesystemCacheReserveMicroseconds

Filesystem cache space reservation time

FilesystemCacheStateLockMicroseconds

Lock filesystem cache time for state lock

FilesystemCacheUnusedHoldFileSegments

Filesystem cache file segments count, which were hold, but not used (because of seek or LIMIT n, etc)

FilterPartsByVirtualColumnsMicroseconds

Total time spent in filterPartsByVirtualColumns function.

FilterTransformPassedBytes

Number of bytes that passed the filter in the query

FilterTransformPassedRows

Number of rows that passed the filter in the query

FilteringMarksWithPrimaryKeyMicroseconds

Time spent filtering parts by PK.

FilteringMarksWithPrimaryKeyProcessedMarks

Total marks processed during PK analysis.

FilteringMarksWithSecondaryKeysMicroseconds

Time spent filtering parts by skip indexes.

FunctionExecute

Number of SQL ordinary function calls (SQL functions are called on per-block basis, so this number represents the number of blocks).

GatheredColumns

Number of columns gathered during the vertical stage of merges.

GatheringColumnMilliseconds

Total time spent while gathering columns for vertical merge

GlobalThreadPoolExpansions

Counts the total number of times new threads have been added to the global thread pool. This metric indicates the frequency of expansions in the global thread pool to accommodate increased processing demands.

GlobalThreadPoolJobWaitTimeMicroseconds

Measures the elapsed time from when a job is scheduled in the thread pool to when it is picked up for execution by a worker thread. This metric helps identify delays in job processing, indicating the responsiveness of the thread pool to new tasks.

GlobalThreadPoolJobs

Counts the number of jobs that have been pushed to the global thread pool.

GlobalThreadPoolLockWaitMicroseconds

Total time threads have spent waiting for locks in the global thread pool.

GlobalThreadPoolShrinks

Counts the total number of times the global thread pool has shrunk by removing threads. This occurs when the number of idle threads exceeds max_thread_pool_free_size, indicating adjustments in the global thread pool size in response to decreased thread utilization.

GlobalThreadPoolThreadCreationMicroseconds

Total time spent waiting for new threads to start.

HTTPConnectionsCreated

Number of created client HTTP connections

HTTPConnectionsElapsedMicroseconds

Total time spend on creating client HTTP connections

HTTPConnectionsErrors

Number of cases when creation of a client HTTP connection failed

HTTPConnectionsExpired

Number of expired client HTTP connections

HTTPConnectionsPreserved

Number of preserved client HTTP connections

HTTPConnectionsReset

Number of reset client HTTP connections

HTTPConnectionsReused

Number of reused client HTTP connections

HTTPServerConnectionsClosed

Number of closed server HTTP connections. Keep alive has not been negotiated

HTTPServerConnectionsCreated

Number of created server HTTP connections

HTTPServerConnectionsExpired

Number of expired server HTTP connections.

HTTPServerConnectionsPreserved

Number of preserved server HTTP connections. Connection kept alive successfully

HTTPServerConnectionsReset

Number of reset server HTTP connections. Server closes connection

HTTPServerConnectionsReused

Number of reused server HTTP connections

HardPageFaults

The number of hard page faults in query execution threads. High values indicate either that you forgot to turn off swap on your server, or eviction of memory pages of the ClickHouse binary during very high memory pressure, or successful usage of the ‘mmap’ read method for the tables data.

HashJoinPreallocatedElementsInHashTables

How many elements were preallocated in hash tables for hash join.

HedgedRequestsChangeReplica

Total count when timeout for changing replica expired in hedged requests.

IOBufferAllocBytes

Number of bytes allocated for IO buffers (for ReadBuffer/WriteBuffer).

IOBufferAllocs

Number of allocations of IO buffers (for ReadBuffer/WriteBuffer).

IOUringCQEsCompleted

Total number of successfully completed io_uring CQEs

IOUringCQEsFailed

Total number of completed io_uring CQEs with failures

IOUringSQEsResubmitsAsync

Total number of asynchronous io_uring SQE resubmits performed

IOUringSQEsResubmitsSync

Total number of synchronous io_uring SQE resubmits performed

IOUringSQEsSubmitted

Total number of io_uring SQEs submitted

IcebergIteratorInitializationMicroseconds

Total time spent on synchronous initialization of iceberg data iterators.

IcebergMetadataFilesCacheHits

Number of times iceberg metadata files have been found in the cache.

IcebergMetadataFilesCacheMisses

Number of times iceberg metadata files have not been found in the iceberg metadata cache and had to be read from (remote) disk.

IcebergMetadataFilesCacheStaleMisses

Number of times iceberg metadata files have been found in the cache, but were considered stale and had to be read from (remote) disk.

IcebergMetadataFilesCacheWeightLost

Approximate number of bytes evicted from the iceberg metadata cache.

IcebergMetadataReadWaitTimeMicroseconds

Total time data readers spend waiting for iceberg metadata files to be read and parsed, summed across all reader threads.

IcebergMetadataReturnedObjectInfos

Total number of returned object infos from iceberg iterator.

IcebergMetadataUpdateMicroseconds

Total time spent on synchronous initialization of iceberg data iterators.

IcebergMinMaxIndexPrunedFiles

Number of skipped files by using MinMax index in Iceberg

IcebergMinMaxNonPrunedDeleteFiles

Total number of accepted data files-position delete file pairs by minmax analysis from pairs suitable by partitioning and sequence number.

IcebergMinMaxPrunedDeleteFiles

Total number of accepted data files-position delete file pairs by minmax analysis from pairs suitable by partitioning and sequence number.

IcebergPartitionPrunedFiles

Number of skipped files during Iceberg partition pruning

IcebergTrivialCountOptimizationApplied

Trivial count optimization applied while reading from Iceberg

IcebergVersionHintUsed

Number of times version-hint.text has been used.

IgnoredColdParts

See setting ignore_cold_parts_seconds. Number of times read queries ignored very new parts that weren’t pulled into cache by CacheWarmer yet.

IndexAnalysisRounds

Number of times index analysis was performed within the query.

IndexBinarySearchAlgorithm

Number of times the binary search algorithm is used over the index marks

IndexGenericExclusionSearchAlgorithm

Number of times the generic exclusion search algorithm is used over the index marks

InitialQuery

Same as Query, but only counts initial queries (see is_initial_query).

InitialSelectQuery

Same as InitialQuery, but only for SELECT queries.

InsertQueriesWithSubqueries

Count INSERT queries with all subqueries

InsertQuery

Same as Query, but only for INSERT queries.

InsertQueryTimeMicroseconds

Total time of INSERT queries.

InsertedBytes

Number of bytes (uncompressed; for columns as they stored in memory) INSERTed to all tables.

InsertedCompactParts

Number of parts inserted in Compact format.

InsertedRows

Number of rows INSERTed to all tables.

InsertedWideParts

Number of parts inserted in Wide format.

InterfaceHTTPReceiveBytes

Number of bytes received through HTTP interfaces

InterfaceHTTPSendBytes

Number of bytes sent through HTTP interfaces

InterfaceInterserverReceiveBytes

Number of bytes received through interserver interfaces

InterfaceInterserverSendBytes

Number of bytes sent through interserver interfaces

InterfaceMySQLReceiveBytes

Number of bytes received through MySQL interfaces

InterfaceMySQLSendBytes

Number of bytes sent through MySQL interfaces

InterfaceNativeReceiveBytes

Number of bytes received through native interfaces

InterfaceNativeSendBytes

Number of bytes sent through native interfaces

InterfacePostgreSQLReceiveBytes

Number of bytes received through PostgreSQL interfaces

InterfacePostgreSQLSendBytes

Number of bytes sent through PostgreSQL interfaces

InterfacePrometheusReceiveBytes

Number of bytes received through Prometheus interfaces

InterfacePrometheusSendBytes

Number of bytes sent through Prometheus interfaces

JemallocFailedAllocationSampleTracking

Total number of times tracking of jemalloc allocation sample failed

JemallocFailedDeallocationSampleTracking

Total number of times tracking of jemalloc deallocation sample failed

JoinBuildPostProcessingMicroseconds

Elapsed time of post-processing steps after building the right JOIN side.

JoinBuildTableRowCount

Total number of rows in the build table for a JOIN operation.

JoinDelayedJoinedTransformBlockCount

Number of blocks emitted by DelayedJoinedBlocksWorkerTransform.

JoinDelayedJoinedTransformRowCount

Number of rows emitted by DelayedJoinedBlocksWorkerTransform.

JoinNonJoinedTransformBlockCount

Number of blocks emitted by NonJoinedBlocksTransform.

JoinNonJoinedTransformRowCount

Number of non-joined rows emitted by NonJoinedBlocksTransform.

JoinOptimizeMicroseconds

Total time spent executing JOIN plan optimizations.

JoinProbeTableRowCount

Total number of rows in the probe table for a JOIN operation.

JoinReorderMicroseconds

Total time spent executing JOIN reordering algorithm.

JoinResultRowCount

Total number of rows in the result of a JOIN operation.

JoinSpillingHashJoinSwitchedToGraceJoin

Number of times a (Concurrent)HashJoin was switched to GraceHashJoin due to memory limit in SpillingHashJoin.

KafkaBackgroundReads

Number of background reads populating materialized views from Kafka since server start

KafkaCommitFailures

Number of failed commits of consumed offsets to Kafka (usually is a sign of some data duplication)

KafkaCommits

Number of successful commits of consumed offsets to Kafka (normally should be the same as KafkaBackgroundReads)

KafkaConsumerErrors

Number of errors reported by librdkafka during polls

KafkaDirectReads

Number of direct selects from Kafka tables since server start

KafkaMVNotReady

Number of failed attempts to stream data to a materialized view that is not ready

KafkaMessagesFailed

Number of Kafka messages ClickHouse failed to parse

KafkaMessagesPolled

Number of Kafka messages polled from librdkafka to ClickHouse

KafkaMessagesProduced

Number of messages produced to Kafka

KafkaMessagesRead

Number of Kafka messages already processed by ClickHouse

KafkaProducerErrors

Number of errors during producing the messages to Kafka

KafkaProducerFlushes

Number of explicit flushes to Kafka producer

KafkaRebalanceAssignments

Number of partition assignments (the final stage of consumer group rebalance)

KafkaRebalanceErrors

Number of failed consumer group rebalances

KafkaRebalanceRevocations

Number of partition revocations (the first stage of consumer group rebalance)

KafkaRowsRead

Number of rows parsed from Kafka messages

KafkaRowsRejected

Number of parsed rows which were later rejected (due to rebalances / errors or similar reasons). Those rows will be consumed again after the rebalance.

KafkaRowsWritten

Number of rows inserted into Kafka tables

KafkaWrites

Number of writes (inserts) to Kafka tables

KeeperAddWatchRequest

Number of add watches requests

KeeperBatchMaxCount

Number of times the size of batch was limited by the amount

KeeperBatchMaxTotalSize

Number of times the size of batch was limited by the total bytes size

KeeperChangelogFileSyncMicroseconds

Time spent in fsync for Keeper changelog (uncompressed logs only)

KeeperChangelogLockWaitMicroseconds

Time spent waiting for acquiring Keeper changelog lock

KeeperChangelogWrittenBytes

Number of bytes written to the changelog in Keeper

KeeperCheckRequest

Number of check requests

KeeperCheckWatchRequest

Number of remove watches requests

KeeperCommitWaitElapsedMicroseconds

Time spent waiting for certain log to be committed

KeeperCommits

Number of successful commits

KeeperCommitsFailed

Number of failed commits

KeeperCreateRequest

Number of create requests

KeeperExistsRequest

Number of exists requests

KeeperGetRequest

Number of get requests

KeeperLatency

Keeper latency

KeeperListRecursiveRequest

Number of get children recursive requests

KeeperListRequest

Number of list requests

KeeperLiveSessionsLockWaitMicroseconds

Time spent waiting to acquire Keeper live sessions lock

KeeperLogsEntryReadFromCommitCache

Number of log entries in Keeper being read from commit logs cache

KeeperLogsEntryReadFromFile

Number of log entries in Keeper being read directly from the changelog file

KeeperLogsEntryReadFromLatestCache

Number of log entries in Keeper being read from latest logs cache

KeeperLogsPrefetchedEntries

Number of log entries in Keeper being prefetched from the changelog file

KeeperMultiReadRequest

Number of multi read requests

KeeperMultiRequest

Number of multi requests

KeeperPacketsReceived

Packets received by keeper server

KeeperPacketsSent

Packets sent by keeper server

KeeperPreprocessElapsedMicroseconds

Keeper preprocessing latency for a single request

KeeperProcessAndResponsesLockWaitMicroseconds

Time spent waiting for acquiring Keeper process and responses lock

KeeperProcessElapsedMicroseconds

Keeper commit latency for a single request

KeeperReadBatchCount

Number of read request batches processed by Keeper

KeeperReadBatchTotalRequests

Total number of read requests processed in batches by Keeper

KeeperReadRequestQueueLockWaitMicroseconds

Time spent waiting for acquiring Keeper read request queue lock

KeeperReadSnapshot

Number of completed snapshot reads

KeeperReadSnapshotFailed

Number of failed snapshot reads

KeeperReadSnapshotObject

Number of snapshot objects sent to followers

KeeperReconfigRequest

Number of reconfig requests

KeeperRemoveRequest

Number of remove requests

KeeperRemoveWatchRequest

Number of remove watches requests

KeeperRequestRejectedDueToSoftMemoryLimitCount

Number requests that have been rejected due to soft memory limit exceeded

KeeperRequestTotal

Total requests number on keeper server

KeeperRequestTotalWithSubrequests

Total requests number on keeper server, counting each subrequest within a multi request

KeeperSaveSnapshot

Number of snapshot save

KeeperSaveSnapshotFailed

Number of failed snapshot saves

KeeperSaveSnapshotObject

Number of snapshot objects received from leader

KeeperServerWriteLockWaitMicroseconds

Time spent waiting for acquiring Keeper server write lock

KeeperSessionCallbackLockWaitMicroseconds

Time spent waiting for acquiring Keeper session callback lock

KeeperSetRequest

Number of set requests

KeeperSetWatchesRequest

Number of set watches requests

KeeperSnapshotApplys

Number of snapshot applying

KeeperSnapshotApplysFailed

Number of failed snapshot applying

KeeperSnapshotCreations

Number of snapshots creations

KeeperSnapshotCreationsFailed

Number of failed snapshot creations

KeeperSnapshotFileSyncMicroseconds

Time spent in fsync for Keeper snapshot files

KeeperSnapshotRemoteLoaderErrors

Number of remote read errors in RemoteSnapshotLoader while serving a snapshot to a follower

KeeperSnapshotWrittenBytes

Number of bytes written to snapshot files in Keeper

KeeperStaleRequestsSkipped

Number of Keeper requests skipped because the session is no longer live

KeeperStorageLockWaitMicroseconds

Time spent waiting for acquiring Keeper storage lock

KeeperStorageSharedLockWaitMicroseconds

Time spent waiting for acquiring Keeper storage shared lock

KeeperTotalElapsedMicroseconds

Keeper total latency for a single request

LoadedDataParts

Number of data parts loaded by MergeTree tables during initialization.

LoadedDataPartsMicroseconds

Microseconds spent by MergeTree tables for loading data parts during initialization.

LoadedMarksCount

Number of marks loaded (total across columns).

LoadedMarksFiles

Number of mark files loaded.

LoadedMarksMemoryBytes

Size of in-memory representations of loaded marks.

LoadedPrimaryIndexBytes

Number of rows of primary key loaded.

LoadedPrimaryIndexFiles

Number of primary index files loaded.

LoadedPrimaryIndexRows

Number of rows of primary key loaded.

LoadedStatisticsMicroseconds

Elapsed time of loading statistics from parts

LoadingMarksTasksCanceled

Number of times background tasks for loading marks were canceled

LocalReadThrottlerBytes

Bytes passed through ‘max_local_read_bandwidth_for_server’/‘max_local_read_bandwidth’ throttler.

LocalReadThrottlerSleepMicroseconds

Total time a query was sleeping to conform ‘max_local_read_bandwidth_for_server’/‘max_local_read_bandwidth’ throttling.

LocalThreadPoolBusyMicroseconds

Total time threads have spent executing the actual work.

LocalThreadPoolExpansions

Counts the total number of times threads have been borrowed from the global thread pool to expand local thread pools.

LocalThreadPoolJobWaitTimeMicroseconds

LocalThreadPoolJobs

Counts the number of jobs that have been pushed to the local thread pools.

LocalThreadPoolLockWaitMicroseconds

Total time threads have spent waiting for locks in the local thread pools.

LocalThreadPoolShrinks

Counts the total number of times threads have been returned to the global thread pool from local thread pools.

LocalThreadPoolThreadCreationMicroseconds

Total time local thread pools have spent waiting to borrow a thread from the global pool.

LocalWriteThrottlerBytes

Bytes passed through ‘max_local_write_bandwidth_for_server’/‘max_local_write_bandwidth’ throttler.

LocalWriteThrottlerSleepMicroseconds

Total time a query was sleeping to conform ‘max_local_write_bandwidth_for_server’/‘max_local_write_bandwidth’ throttling.

LogDebug

Number of log messages with level Debug

LogError

Number of log messages with level Error

LogFatal

Number of log messages with level Fatal

LogInfo

Number of log messages with level Info

LogTest

Number of log messages with level Test

LogTrace

Number of log messages with level Trace

LogWarning

Number of log messages with level Warning

LoggerElapsedNanoseconds

Cumulative time spend in logging

MMappedFileCacheHits

Number of times a file has been found in the MMap cache (for the ‘mmap’ read_method), so we didn’t have to mmap it again.

MMappedFileCacheMisses

Number of times a file has not been found in the MMap cache (for the ‘mmap’ read_method), so we had to mmap it again.

MainConfigLoads

Number of times the main configuration was reloaded.

MarkCacheEvictedBytes

Number of bytes evicted from the mark cache.

MarkCacheEvictedFiles

Number of mark files evicted from the mark cache.

MarkCacheEvictedMarks

Number of marks evicted from the mark cache.

MarkCacheHits

Number of times an entry has been found in the mark cache, so we didn’t have to load a mark file.

MarkCacheMisses

Number of times an entry has not been found in the mark cache, so we had to load a mark file in memory, which is a costly operation, adding to query latency.

MarksTasksFromCache

Number of times marks were loaded synchronously because they were already present in the cache.

MemoryAllocatedWithoutCheck

Number of times memory has been allocated without checking for memory constraints.

MemoryAllocatedWithoutCheckBytes

Amount of bytes that has been allocated without checking for memory constraints.

MemoryAllocatorPurge

Total number of times memory allocator purge was requested

MemoryAllocatorPurgeTimeMicroseconds

Total time spent for memory allocator purge

MemoryOvercommitWaitTimeMicroseconds

Total time spent in waiting for memory to be freed in OvercommitTracker.

MemoryWorkerRun

Number of runs done by MemoryWorker in background

MemoryWorkerRunElapsedMicroseconds

Total time spent by MemoryWorker for background work

Merge

Number of launched background merges.

MergeCommitMilliseconds

Total time spent for committing merge results (part renaming, checksum verification, ZooKeeper updates)

MergeExecuteMilliseconds

Total busy time spent for execution of background merges

MergeHorizontalStageExecuteMilliseconds

Total busy time spent for execution of horizontal stage of background merges

MergeHorizontalStageTotalMilliseconds

Total time spent for horizontal stage of background merges

MergeMutateBackgroundExecutorTaskCancelMicroseconds

Time spent in cancel() for MergeMutate executor tasks.

MergeMutateBackgroundExecutorTaskExecuteStepMicroseconds

Time spent in executeStep() for MergeMutate executor tasks.

MergeMutateBackgroundExecutorTaskResetMicroseconds

Time spent resetting task for MergeMutate executor.

MergeMutateBackgroundExecutorWaitMicroseconds

Time spent waiting for completion in MergeMutate executor.

MergePrewarmStageExecuteMilliseconds

Total busy time spent for execution of prewarm stage of background merges

MergePrewarmStageTotalMilliseconds

Total time spent for prewarm stage of background merges

MergeProjectionStageExecuteMilliseconds

Total busy time spent for execution of projection stage of background merges

MergeProjectionStageTotalMilliseconds

Total time spent for projection stage of background merges

MergeSourceParts

Number of source parts scheduled for merges.

MergeTextIndexStageExecuteMilliseconds

Total busy time spent for execution of text index stage of background merges

MergeTextIndexStageTotalMilliseconds

Total time spent for text index stage of background merges

MergeTotalMilliseconds

Total time spent for background merges

MergeTreeAllRangesAnnouncementsSent

The number of announcements sent from the remote server to the initiator server about the set of data parts (for MergeTree tables). Measured on the remote server side.

MergeTreeAllRangesAnnouncementsSentElapsedMicroseconds

Time spent in sending the announcement from the remote server to the initiator server about the set of data parts (for MergeTree tables). Measured on the remote server side.

MergeTreeDataProjectionWriterBlocks

Number of blocks INSERTed to MergeTree tables projection. Each block forms a data part of level zero.

MergeTreeDataProjectionWriterBlocksAlreadySorted

Number of blocks INSERTed to MergeTree tables projection that appeared to be already sorted.

MergeTreeDataProjectionWriterCompressedBytes

Bytes written to filesystem for data INSERTed to MergeTree tables projection.

MergeTreeDataProjectionWriterMergingBlocksMicroseconds

Time spent merging blocks

MergeTreeDataProjectionWriterRows

Number of rows INSERTed to MergeTree tables projection.

MergeTreeDataProjectionWriterSortingBlocksMicroseconds

Time spent sorting blocks (for projection it might be a key different from table’s sorting key)

MergeTreeDataProjectionWriterUncompressedBytes

Uncompressed bytes (for columns as they stored in memory) INSERTed to MergeTree tables projection.

MergeTreeDataWriterBlocks

Number of blocks INSERTed to MergeTree tables. Each block forms a data part of level zero.

MergeTreeDataWriterBlocksAlreadySorted

Number of blocks INSERTed to MergeTree tables that appeared to be already sorted.

MergeTreeDataWriterCompressedBytes

Bytes written to filesystem for data INSERTed to MergeTree tables.

MergeTreeDataWriterMergingBlocksMicroseconds

Time spent merging input blocks (for special MergeTree engines)

MergeTreeDataWriterProjectionsCalculationMicroseconds

Time spent calculating projections

MergeTreeDataWriterRows

Number of rows INSERTed to MergeTree tables.

MergeTreeDataWriterSkipIndicesCalculationMicroseconds

Time spent calculating skip indices

MergeTreeDataWriterSortingBlocksMicroseconds

Time spent sorting blocks

MergeTreeDataWriterStatisticsCalculationMicroseconds

Time spent calculating statistics

MergeTreeDataWriterUncompressedBytes

Uncompressed bytes (for columns as they stored in memory) INSERTed to MergeTree tables.

MergeTreePrefetchedReadPoolInit

Time spent preparing tasks in MergeTreePrefetchedReadPool

MergeTreeReadTaskRequestsReceived

The number of callbacks requested from the remote server back to the initiator server to choose the read task (for MergeTree tables). Measured on the initiator server side.

MergeTreeReadTaskRequestsSent

The number of callbacks requested from the remote server back to the initiator server to choose the read task (for MergeTree tables). Measured on the remote server side.

MergeTreeReadTaskRequestsSentElapsedMicroseconds

Time spent in callbacks requested from the remote server back to the initiator server to choose the read task (for MergeTree tables). Measured on the remote server side.

MergeVerticalStageExecuteMilliseconds

Total busy time spent for execution of vertical stage of background merges

MergeVerticalStageTotalMilliseconds

Total time spent for vertical stage of background merges

MergeWrittenRows

Number of rows written during the merge.

MergedColumns

Number of columns merged during the horizontal stage of merges.

MergedIntoCompactParts

Number of parts merged into Compact format.

MergedIntoWideParts

Number of parts merged into Wide format.

MergedProjections

Number of projections merged (not rebuilt) during MergeTree merges.

MergedRows

Rows read for background merges. This is the number of rows before merge.

MergedUncompressedBytes

Uncompressed bytes (for columns as they stored in memory) that was read for background merges. This is the number before merge.

MergerMutatorPartsInRangesForMergeCount

Amount of candidate parts for merge

MergerMutatorPrepareRangesForMergeElapsedMicroseconds

Time spent to prepare parts ranges which can be merged according to merge predicate.

MergerMutatorRangesForMergeCount

Amount of candidate ranges for merge

MergerMutatorSelectPartsForMergeElapsedMicroseconds

Time spent to select parts from ranges which can be merged.

MergerMutatorSelectRangePartsCount

Amount of parts in selected range for merge

MergerMutatorsGetPartsForMergeElapsedMicroseconds

Time spent to take data parts snapshot to build ranges from them.

MergesRejectedByMemoryLimit

Number of background merges rejected due to memory limit

MergesThrottlerBytes

Bytes passed through ‘max_merges_bandwidth_for_server’ throttler.

MergesThrottlerSleepMicroseconds

Total time a query was sleeping to conform ‘max_merges_bandwidth_for_server’ throttling.

MergingSortedMilliseconds

Total time spent while merging sorted columns

MetadataFromKeeperBackgroundCleanupBlobs

Number of times an empty blob layout part was cleaned up by background task

MetadataFromKeeperBackgroundCleanupErrors

Number of times an error was encountered in background cleanup task

MetadataFromKeeperBackgroundCleanupObjects

Number of times a old deleted object clean up was performed by background task

MetadataFromKeeperBackgroundCleanupTransactions

Number of times old transaction idempotency token was cleaned up by background task

MetadataFromKeeperCacheHit

Number of times an object storage metadata request was answered from cache without making request to Keeper

MetadataFromKeeperCacheMiss

Number of times an object storage metadata request had to be answered from Keeper

MetadataFromKeeperCacheTooManyInvalidated

Number of times filesystem cache returned too many invalidated entries

MetadataFromKeeperCacheUpdateMicroseconds

Total time spent in updating the cache including waiting for responses from Keeper

MetadataFromKeeperCleanupTransactionCommit

Number of times metadata transaction commit for deleted objects cleanup was attempted

MetadataFromKeeperCleanupTransactionCommitRetry

Number of times metadata transaction commit for deleted objects cleanup was retried

MetadataFromKeeperIndividualOperations

Number of paths read or written by single or multi requests to Keeper

MetadataFromKeeperIndividualOperationsMicroseconds

Time spend during single or multi requests to Keeper

MetadataFromKeeperOperations

Number of times a request was made to Keeper

MetadataFromKeeperReconnects

Number of times a reconnect to Keeper was done

MetadataFromKeeperTransactionCommit

Number of times metadata transaction commit was attempted

MetadataFromKeeperTransactionCommitRetry

Number of times metadata transaction commit was retried

MetadataFromKeeperUpdateCacheOneLevel

Number of times a cache update for one level of directory tree was done

MoveBackgroundExecutorTaskCancelMicroseconds

Time spent in cancel() for Move executor tasks.

MoveBackgroundExecutorTaskExecuteStepMicroseconds

Time spent in executeStep() for Move executor tasks.

MoveBackgroundExecutorTaskResetMicroseconds

Time spent resetting task for Move executor.

MoveBackgroundExecutorWaitMicroseconds

Time spent waiting for completion in Move executor.

MutateTaskProjectionsCalculationMicroseconds

Time spent calculating projections in mutations

MutatedRows

Rows read for mutations. This is the number of rows before mutation

MutatedUncompressedBytes

Uncompressed bytes (for columns as they stored in memory) that was read for mutations. This is the number before mutation.

MutationAffectedRowsUpperBound

The upper bound of number of rows that were affected by mutation (e.g. number of rows that satisfy the predicate of UPDATE or DELETE mutation). The actual number may be slightly less

MutationAllPartColumns

Number of times when task to mutate all columns in part was created

MutationCommitMilliseconds

Total time spent for committing mutation results (part renaming, checksum verification, ZooKeeper updates)

MutationCreatedEmptyParts

Number of total parts which were replaced to empty parts instead of running mutation

MutationExecuteMilliseconds

Total busy time spent for execution of mutations.

MutationSomePartColumns

Number of times when task to mutate some columns in part was created

MutationTotalMilliseconds

Total time spent for mutations.

MutationTotalParts

Number of total parts for which mutations tried to be applied

MutationUntouchedParts

Number of total parts for which mutations tried to be applied but which was completely skipped according to predicate

MutationsAppliedOnFlyInAllReadTasks

Total number of applied mutations on-fly among all read tasks

MutationsThrottlerBytes

Bytes passed through ‘max_mutations_bandwidth_for_server’ throttler.

MutationsThrottlerSleepMicroseconds

Total time a query was sleeping to conform ‘max_mutations_bandwidth_for_server’ throttling.

NaiveBayesClassifierModelsAllocatedBytes

Number of bytes allocated for Naive Bayes Classifier models.

NaiveBayesClassifierModelsLoaded

Number of Naive Bayes Classifier models loaded.

NetworkReceiveBytes

Total number of bytes received from network. Only ClickHouse-related network interaction is included, not by 3rd party libraries.

NetworkReceiveElapsedMicroseconds

Total time spent waiting for data to receive or receiving data from network. Only ClickHouse-related network interaction is included, not by 3rd party libraries.

NetworkSendBytes

Total number of bytes send to network. Only ClickHouse-related network interaction is included, not by 3rd party libraries.

NetworkSendElapsedMicroseconds

Total time spent waiting for data to send to network or sending data to network. Only ClickHouse-related network interaction is included, not by 3rd party libraries.

NotCreatedLogEntryForMerge

Log entry to merge parts in ReplicatedMergeTree is not created due to concurrent log update by another replica.

NotCreatedLogEntryForMutation

Log entry to mutate parts in ReplicatedMergeTree is not created due to concurrent log update by another replica.

OSCPUVirtualTimeMicroseconds

CPU time spent seen by OS. Does not include involuntary waits due to virtualization.

OSCPUWaitMicroseconds

Total time a thread was ready for execution but waiting to be scheduled by OS, from the OS point of view.

OSIOWaitMicroseconds

Total time a thread spent waiting for a result of IO operation, from the OS point of view. This is real IO that doesn’t include page cache.

OSReadBytes

Number of bytes read from disks or block devices. Doesn’t include bytes read from page cache. May include excessive data due to block size, readahead, etc.

OSReadChars

Number of bytes read from filesystem, including page cache, as well as network and other files.

OSWriteBytes

Number of bytes written to disks or block devices. Doesn’t include bytes that are in page cache dirty pages. May not include data that was written by OS asynchronously.

OSWriteChars

Number of bytes written to filesystem, including page cache, as well as network and other files.

ObjectStorageGlobFilteredObjects

Objects that did not match the glob or regex pattern and were skipped during listing.

ObjectStorageListedObjects

Total objects returned by object storage listing API before any filtering.

ObjectStoragePredicateFilteredObjects

Objects removed by virtual column predicate filtering on _path/_file.

ObjectStorageQueueCancelledFiles

Number cancelled files in StorageS3(Azure)Queue

ObjectStorageQueueCleanupMaxSetSizeOrTTLMicroseconds

Time spent to set file as failed

ObjectStorageQueueCommitRequests

Number of keeper requests to commit files as either failed or processed

ObjectStorageQueueExceptionsDuringInsert

Number of exceptions during insert in S3(Azure)Queue

ObjectStorageQueueExceptionsDuringRead

Number of exceptions during read in S3(Azure)Queue

ObjectStorageQueueFailedFiles

Number of files which failed to be processed

ObjectStorageQueueFailedToBatchSetProcessing

Number of times batched set processing request failed

ObjectStorageQueueFilteredFiles

Number of filtered files in StorageS3(Azure)Queue

ObjectStorageQueueInsertIterations

Number of insert iterations

ObjectStorageQueueListedFiles

Number of listed files in StorageS3(Azure)Queue

ObjectStorageQueueMovedObjects

Number of objects moved as part of after_processing = move

ObjectStorageQueueProcessedFiles

Number of files which were processed

ObjectStorageQueueProcessedRows

Number of processed rows in StorageS3(Azure)Queue

ObjectStorageQueuePullMicroseconds

Time spent to read file data

ObjectStorageQueueReadBytes

Number of read bytes (not equal to the number of actually inserted bytes)

ObjectStorageQueueReadFiles

Number of read files (not equal to the number of actually inserted files)

ObjectStorageQueueReadRows

Number of read rows (not equal to the number of actually inserted rows)

ObjectStorageQueueRemovedObjects

Number of objects removed as part of after_processing = delete

ObjectStorageQueueSuccessfulCommits

Number of successful keeper commits

ObjectStorageQueueTaggedObjects

Number of objects tagged as part of after_processing = tag

ObjectStorageQueueTrySetProcessingFailed

The number of times we unsuccessfully set file as processing

ObjectStorageQueueTrySetProcessingRequests

The number of times we tried to make set processing request

ObjectStorageQueueTrySetProcessingSucceeded

The number of times we successfully set file as processing

ObjectStorageQueueUnsuccessfulCommits

Number of unsuccessful keeper commits

ObjectStorageReadObjects

Objects actually opened for reading by the object storage source.

ObsoleteReplicatedParts

Number of times a data part was covered by another data part that has been fetched from a replica (so, we have marked a covered data part as obsolete and no longer needed).

OpenedFileCacheHits

Number of times a file has been found in the opened file cache, so we didn’t have to open it again.

OpenedFileCacheMicroseconds

Amount of time spent executing OpenedFileCache methods.

OpenedFileCacheMisses

Number of times a file has been found in the opened file cache, so we had to open it again.

OtherQueryTimeMicroseconds

Total time of queries that are not SELECT or INSERT.

OverflowAny

Number of times approximate GROUP BY was in effect: when aggregation was performed only on top of first ‘max_rows_to_group_by’ unique keys and other keys were ignored due to ‘group_by_overflow_mode’ = ‘any’.

OverflowBreak

Number of times, data processing was cancelled by query complexity limitation with setting ’*_overflow_mode’ = ‘break’ and the result is incomplete.

OverflowThrow

Number of times, data processing was cancelled by query complexity limitation with setting ’*_overflow_mode’ = ‘throw’ and exception was thrown.

PageCacheHits

Number of times a block of data has been found in the userspace page cache.

PageCacheMisses

Number of times a block of data has not been found in the userspace page cache.

PageCacheOvercommitResize

Number of times the userspace page cache was auto-resized to free memory during a memory allocation.

PageCacheReadBytes

Number of bytes read from userspace page cache.

PageCacheResized

Number of times the userspace page cache was auto-resized (typically happens a few times per second, controlled by memory_worker_period_ms).

PageCacheWeightLost

Number of bytes evicted from the userspace page cache

ParallelReplicasAnnouncementMicroseconds

Time spent to send an announcement

ParallelReplicasAvailableCount

Number of replicas available to execute a query with task-based parallel replicas

ParallelReplicasCollectingOwnedSegmentsMicroseconds

Time spent collecting segments meant by hash

ParallelReplicasDeniedRequests

Number of completely denied requests to the initiator

ParallelReplicasHandleAnnouncementMicroseconds

Time spent processing replicas announcements

ParallelReplicasHandleRequestMicroseconds

Time spent processing requests for marks from replicas

ParallelReplicasNumRequests

Number of requests to the initiator.

ParallelReplicasProcessingPartsMicroseconds

Time spent processing data parts

ParallelReplicasQueryCount

Number of (sub)queries executed using parallel replicas during a query execution

ParallelReplicasReadAssignedForStealingMarks

Sum across all replicas of how many of scheduled marks were assigned for stealing by consistent hash

ParallelReplicasReadAssignedMarks

Sum across all replicas of how many of scheduled marks were assigned by consistent hash

ParallelReplicasReadMarks

How many marks were read by the given replica

ParallelReplicasReadRequestMicroseconds

Time spent for read requests

ParallelReplicasReadUnassignedMarks

Sum across all replicas of how many unassigned marks were scheduled

ParallelReplicasStealingByHashMicroseconds

Time spent collecting segments meant for stealing by hash

ParallelReplicasStealingLeftoversMicroseconds

Time spent collecting orphaned segments

ParallelReplicasUnavailableCount

Number of replicas which was chosen, but found to be unavailable during query execution with task-based parallel replicas

ParallelReplicasUsedCount

Number of replicas used to execute a query with task-based parallel replicas

ParquetColumnsFilterExpression

The total number of columns that were passed through filter

ParquetDecodingTaskBatches

Task groups sent to a thread pool by parquet reader

ParquetDecodingTasks

Tasks issued by parquet reader

ParquetFetchWaitTimeMicroseconds

Time of waiting for parquet file reads from decoding threads (not prefetching threads)

ParquetMetadataCacheHits

Number of times parquet metadata has been found in the cache.

ParquetMetadataCacheMisses

Number of times parquet metadata has not been found in the cache and had to be read from disk.

ParquetMetadataCacheWeightLost

Approximate number of bytes evicted from the parquet metadata cache.

ParquetPrefetcherReadEntireFile

The total number of read with ReadMode::EntireFileIsInMemory by DB::Parquet::Prefetcher

ParquetPrefetcherReadRandomRead

The total number of reads with ReadMode::RandomRead by DB::Parquet::Prefetcher

ParquetPrefetcherReadSeekAndRead

The total number of reads with ReadMode::SeekAndRead by DB::Parquet::Prefetcher

ParquetPrunedRowGroups

The total number of row groups pruned from parquet data

ParquetReadRowGroups

The total number of row groups read from parquet data

ParquetRowsFilterExpression

The total number of rows that were passed through filter

PartsLockHoldMicroseconds

Total time spent holding data parts lock in MergeTree tables

PartsLockWaitMicroseconds

Total time spent waiting for data parts lock in MergeTree tables

PartsLocks

Number of times data parts lock has been acquired for MergeTree tables

PatchesAcquireLockMicroseconds

Total number of microseconds spent to acquire lock for executing lightweight updates

PatchesAcquireLockTries

Total number of tries to acquire lock for executing lightweight updates

PatchesAppliedInAllReadTasks

Total number of applied patch parts among all read tasks

PatchesJoinAppliedInAllReadTasks

Total number of applied patch parts with Join mode among all read tasks

PatchesJoinRowsAddedToHashTable

Total number of rows added to hash tables when applying patch parts with Join mode

PatchesMergeAppliedInAllReadTasks

Total number of applied patch parts with Merge mode among all read tasks

PatchesReadRows

Total number of rows read from patch parts

PatchesReadUncompressedBytes

Total number of uncompressed bytes read from patch parts

PerfAlignmentFaults

Number of alignment faults. These happen when unaligned memory accesses happen; the kernel can handle these but it reduces performance. This happens only on some architectures (never on x86).

PerfBranchInstructions

Retired branch instructions. Prior to Linux 2.6.35, this used the wrong event on AMD processors.

PerfBranchMisses

Mispredicted branch instructions.

PerfBusCycles

Bus cycles, which can be different from total cycles.

PerfCPUClock

The CPU clock, a high-resolution per-CPU timer

PerfCPUCycles

Total cycles. Be wary of what happens during CPU frequency scaling.

PerfCPUMigrations

Number of times the process has migrated to a new CPU

PerfCacheMisses

Cache misses. Usually this indicates Last Level Cache misses; this is intended to be used in conjunction with the PERFCOUNTHWCACHEREFERENCES event to calculate cache miss rates.

PerfCacheReferences

Cache accesses. Usually, this indicates Last Level Cache accesses, but this may vary depending on your CPU. This may include prefetches and coherency messages; again this depends on the design of your CPU.

PerfContextSwitches

Number of context switches

PerfDataTLBMisses

Data TLB misses

PerfDataTLBReferences

Data TLB references

PerfEmulationFaults

Number of emulation faults. The kernel sometimes traps on unimplemented instructions and emulates them for user space. This can negatively impact performance.

PerfInstructionTLBMisses

Instruction TLB misses

PerfInstructionTLBReferences

Instruction TLB references

PerfInstructions

Retired instructions. Be careful, these can be affected by various issues, most notably hardware interrupt counts.

PerfLocalMemoryMisses

Local NUMA node memory read misses

PerfLocalMemoryReferences

Local NUMA node memory reads

PerfMinEnabledRunningTime

Running time for event with minimum enabled time. Used to track the amount of event multiplexing

PerfMinEnabledTime

For all events, minimum time that an event was enabled. Used to track event multiplexing influence

PerfRefCPUCycles

Total cycles; not affected by CPU frequency scaling.

PerfStalledCyclesBackend

Stalled cycles during retirement.

PerfStalledCyclesFrontend

Stalled cycles during issue.

PerfTaskClock

A clock count specific to the task that is running

PolygonsAddedToPool

A polygon has been added to the cache (pool) for the ‘pointInPolygon’ function.

PolygonsInPoolAllocatedBytes

The number of bytes for polygons added to the cache (pool) for the ‘pointInPolygon’ function.

PreferredWarmedUnmergedParts

See setting prefer_warmed_unmerged_parts_seconds. Number of times read queries used outdated pre-merge parts that are in cache instead of merged part that wasn’t pulled into cache by CacheWarmer yet.

PrimaryIndexCacheHits

Number of times an entry has been found in the primary index cache, so we didn’t have to load a index file.

PrimaryIndexCacheMisses

Number of times an entry has not been found in the primary index cache, so we had to load a index file in memory, which is a costly operation, adding to query latency.

QueriesWithSubqueries

Count queries with all subqueries

Query

Number of queries to be interpreted and potentially executed. Does not include queries that failed to parse or were rejected due to AST size limits, quota limits or limits on the number of simultaneously running queries. May include internal queries initiated by ClickHouse itself. Does not count subqueries.

QueryBackupThrottlerBytes

Bytes passed through ‘max_backup_bandwidth’ throttler.

QueryBackupThrottlerSleepMicroseconds

Total time a query was sleeping to conform ‘max_backup_bandwidth’ throttling.

QueryCacheAgeSeconds

The sum of ages of found query cache entries in seconds. The value is set both for hits and misses.

QueryCacheHits

Number of times a query result has been found in the query cache (and query computation was avoided). Only updated for SELECT queries with SETTING use_query_cache = 1.

QueryCacheMisses

Number of times a query result has not been found in the query cache (and required query computation). Only updated for SELECT queries with SETTING use_query_cache = 1.

QueryCacheReadBytes

The number of (uncompressed) bytes read from the query cache.

QueryCacheReadRows

The number of rows read from the query cache.

QueryCacheWrittenBytes

The number of (uncompressed) bytes saved into the query cache

QueryCacheWrittenRows

The number of rows saved into the query cache.

QueryConditionCacheHits

Number of times an entry has been found in the query condition cache (and reading of marks can be skipped). Only updated for SELECT queries with SETTING use_query_condition_cache = 1.

QueryConditionCacheMisses

Number of times an entry has not been found in the query condition cache (and reading of mark cannot be skipped). Only updated for SELECT queries with SETTING use_query_condition_cache = 1.

QueryLocalReadThrottlerBytes

Bytes passed through ‘max_local_read_bandwidth’ throttler.

QueryLocalReadThrottlerSleepMicroseconds

Total time a query was sleeping to conform ‘max_local_read_bandwidth’ throttling.

QueryLocalWriteThrottlerBytes

Bytes passed through ‘max_local_write_bandwidth’ throttler.

QueryLocalWriteThrottlerSleepMicroseconds

Total time a query was sleeping to conform ‘max_local_write_bandwidth’ throttling.

QueryMaskingRulesMatch

Number of times query masking rules was successfully matched.

QueryMemoryLimitExceeded

Number of times when memory limit exceeded for query.

QueryPlanOptimizeMicroseconds

Total time spent executing query plan optimizations.

QueryPreempted

How many times tasks are paused and waiting due to ‘priority’ setting

QueryProfilerConcurrencyOverruns

Number of times we drop processing of a query profiler signal due to too many concurrent query profilers in other threads, which may indicate overload.

QueryProfilerErrors

Invalid memory accesses during asynchronous stack unwinding.

QueryProfilerRuns

Number of times QueryProfiler had been run.

QueryProfilerSignalOverruns

Number of times we drop processing of a query profiler signal due to overrun plus the number of signals that OS has not delivered due to overrun.

QueryRemoteReadThrottlerBytes

Bytes passed through ‘max_remote_read_network_bandwidth’ throttler.

QueryRemoteReadThrottlerSleepMicroseconds

Total time a query was sleeping to conform ‘max_remote_read_network_bandwidth’ throttling.

QueryRemoteWriteThrottlerBytes

Bytes passed through ‘max_remote_write_network_bandwidth’ throttler.

QueryRemoteWriteThrottlerSleepMicroseconds

Total time a query was sleeping to conform ‘max_remote_write_network_bandwidth’ throttling.

QueryTimeMicroseconds

Total time of all queries.

QuorumFailedInserts

Number of inserts failed due to quorum not reaching.

QuorumParts

Number of data parts written with quorum. It counts as one part for sync insert and maybe up to async inserts count for insert which flushes async inserts.

QuorumWaitMicroseconds

Total time spent waiting for quorum during inserts.

RWLockAcquiredReadLocks

Number of times a read lock was acquired (in a heavy RWLock).

RWLockAcquiredWriteLocks

Number of times a write lock was acquired (in a heavy RWLock).

RWLockReadersWaitMilliseconds

Total time spent waiting for a read lock to be acquired (in a heavy RWLock).

RWLockWritersWaitMilliseconds

Total time spent waiting for a write lock to be acquired (in a heavy RWLock).

ReadBackoff

Number of times the number of query processing threads was lowered due to slow reads.

ReadBufferFromAzureBytes

Bytes read from Azure.

ReadBufferFromAzureInitMicroseconds

Time spent initializing connection to Azure.

ReadBufferFromAzureMicroseconds

Time spent on reading from Azure.

ReadBufferFromAzureRequestsErrors

Number of exceptions while reading from Azure

ReadBufferFromFileDescriptorRead

Number of reads (read/pread) from a file descriptor. Does not include sockets.

ReadBufferFromFileDescriptorReadBytes

Number of bytes read from file descriptors. If the file is compressed, this will show the compressed data size.

ReadBufferFromFileDescriptorReadFailed

Number of times the read (read/pread) from a file descriptor have failed.

ReadBufferFromS3Bytes

Bytes read from S3.

ReadBufferFromS3InitMicroseconds

Time spent initializing connection to S3.

ReadBufferFromS3Microseconds

Time spent on reading from S3.

ReadBufferFromS3RequestsErrors

Number of exceptions while reading from S3.

ReadBufferSeekCancelConnection

Number of seeks which lead to new connection (s3, http)

ReadCompressedBytes

Number of bytes (the number of bytes before decompression) read from compressed sources (files, network).

ReadPatchesMicroseconds

Total time spent reading patch parts

ReadTaskRequestsReceived

The number of callbacks requested from the remote server back to the initiator server to choose the read task (for s3Cluster table function and similar). Measured on the initiator server side.

ReadTaskRequestsSent

The number of callbacks requested from the remote server back to the initiator server to choose the read task (for s3Cluster table function and similar). Measured on the remote server side.

ReadTaskRequestsSentElapsedMicroseconds

Time spent in callbacks requested from the remote server back to the initiator server to choose the read task (for s3Cluster table function and similar). Measured on the remote server side.

ReadTasksWithAppliedMutationsOnFly

Total number of read tasks for which there was any mutation applied on fly

ReadTasksWithAppliedPatches

Total number of read tasks for which there was any patch part applied

ReadWriteBufferFromHTTPBytes

Total size of payload bytes received and sent by ReadWriteBufferFromHTTP. Doesn’t include HTTP headers.

ReadWriteBufferFromHTTPRequestsSent

Number of HTTP requests sent by ReadWriteBufferFromHTTP

RealTimeMicroseconds

Total (wall clock) time spent in processing (queries and other tasks) threads (note that this is a sum).

RebuiltProjections

Number of projections rebuilt from scratch during MergeTree merges.

RefreshableViewLockTableRetry

How many times a SELECT from refreshable materialized view had to switch to a new table because the old table was dropped

RefreshableViewRefreshFailed

How many times refreshable materialized views failed to refresh

RefreshableViewRefreshSuccess

How many times refreshable materialized views refreshed

RefreshableViewSyncReplicaRetry

How many times a SELECT from refreshable materialized view failed and retried an implicit SYNC REPLICA

RefreshableViewSyncReplicaSuccess

How many times a SELECT from refreshable materialized view did an implicit SYNC REPLICA

RegexpLocalCacheHit

Number of times we fetched compiled regular expression from a local cache.

RegexpLocalCacheMiss

Number of times we failed to fetch compiled regular expression from a local cache.

RegexpWithMultipleNeedlesCreated

Regular expressions with multiple needles (VectorScan library) compiled.

RegexpWithMultipleNeedlesGlobalCacheHit

Number of times we fetched compiled regular expression with multiple needles (VectorScan library) from the global cache.

RegexpWithMultipleNeedlesGlobalCacheMiss

Number of times we failed to fetch compiled regular expression with multiple needles (VectorScan library) from the global cache.

RejectedInserts

Number of times the INSERT of a block to a MergeTree table was rejected with ‘Too many parts’ exception due to high number of active data parts for partition.

RejectedLightweightUpdates

Number of time the lightweight update was rejected due to too many uncompressed bytes in patches.

RejectedMutations

Number of times the mutation of a MergeTree table was rejected with ‘Too many mutations’ exception due to high number of unfinished mutations for table.

RemoteFSBuffers

Number of buffers created for asynchronous reading from remote filesystem

RemoteFSCancelledPrefetches

Number of cancelled prefecthes (because of seek)

RemoteFSLazySeeks

Number of lazy seeks

RemoteFSPrefetchedBytes

Number of bytes from prefecthed buffer

RemoteFSPrefetchedReads

Number of reads from prefecthed buffer

RemoteFSPrefetches

Number of prefetches made with asynchronous reading from remote filesystem

RemoteFSSeeks

Total number of seeks for async buffer

RemoteFSSeeksWithReset

Number of seeks which lead to a new connection

RemoteFSUnprefetchedBytes

Number of bytes from unprefetched buffer

RemoteFSUnprefetchedReads

Number of reads from unprefetched buffer

RemoteFSUnusedPrefetches

Number of prefetches pending at buffer destruction

RemoteReadThrottlerBytes

Bytes passed through ‘max_remote_read_network_bandwidth_for_server’/‘max_remote_read_network_bandwidth’ throttler.

RemoteReadThrottlerSleepMicroseconds

Total time a query was sleeping to conform ‘max_remote_read_network_bandwidth_for_server’/‘max_remote_read_network_bandwidth’ throttling.

RemoteWriteThrottlerBytes

Bytes passed through ‘max_remote_write_network_bandwidth_for_server’/‘max_remote_write_network_bandwidth’ throttler.

RemoteWriteThrottlerSleepMicroseconds

Total time a query was sleeping to conform ‘max_remote_write_network_bandwidth_for_server’/‘max_remote_write_network_bandwidth’ throttling.

ReplacingSortedMilliseconds

Total time spent while replacing sorted columns

ReplicaPartialShutdown

How many times Replicated table has to deinitialize its state due to session expiration in ZooKeeper. The state is reinitialized every time when ZooKeeper is available again.

ReplicatedCoveredPartsInZooKeeperOnStart

For debugging purposes. Number of parts in ZooKeeper that have a covering part, but doesn’t exist on disk. Checked on server start.

ReplicatedDataLoss

Number of times a data part that we wanted doesn’t exist on any replica (even on replicas that are offline right now). That data parts are definitely lost. This is normal due to asynchronous replication (if quorum inserts were not enabled), when the replica on which the data part was written was failed and when it became online after fail it doesn’t contain that data part.

ReplicatedPartChecks

Number of times we had to perform advanced search for a data part on replicas or to clarify the need of an existing data part.

ReplicatedPartChecksFailed

Number of times the advanced search for a data part on replicas did not give result or when unexpected part has been found and moved away.

ReplicatedPartFailedFetches

Number of times a data part was failed to download from replica of a ReplicatedMergeTree table.

ReplicatedPartFetches

Number of times a data part was downloaded from replica of a ReplicatedMergeTree table.

ReplicatedPartFetchesOfMerged

Number of times we prefer to download already merged part from replica of ReplicatedMergeTree table instead of performing a merge ourself (usually we prefer doing a merge ourself to save network traffic). This happens when we have not all source parts to perform a merge or when the data part is old enough.

ReplicatedPartMerges

Number of times data parts of ReplicatedMergeTree tables were successfully merged.

ReplicatedPartMutations

Number of times data parts of ReplicatedMergeTree tables were successfully mutated.

RestorePartsSkippedBytes

Total size of files skipped while restoring parts

RestorePartsSkippedFiles

Number of files skipped while restoring parts

RowsReadByMainReader

Number of rows read from MergeTree tables by the main reader (after PREWHERE step).

RowsReadByPrewhereReaders

Number of rows read from MergeTree tables (in total) by prewhere readers.

RuntimeDataflowStatisticsInputBytes

Collected statistics on the number of bytes replicas would read if the query was executed with parallel replicas

RuntimeDataflowStatisticsOutputBytes

Collected statistics on the number of bytes replicas would send to the initiator if the query was executed with parallel replicas

RuntimeFilterBlocksProcessed

Number of blocks processed by JOIN Runtime Filters

RuntimeFilterBlocksSkipped

Number of blocks skipped by JOIN Runtime Filters without processing due to filter being dynamically disabled because of poor filtering ratio

RuntimeFilterRowsChecked

Number of rows checked by JOIN Runtime Filters

RuntimeFilterRowsPassed

Number of rows that passed (not filtered out by) JOIN Runtime Filters

RuntimeFilterRowsSkipped

Number of rows in blocks that were skipped by JOIN Runtime Filters

RuntimeFiltersCreated

Number of distinct JOIN Runtime Filters created within a query

S3AbortMultipartUpload

Number of S3 API AbortMultipartUpload calls.

S3CachedCredentialsProvidersAdded

Total number of newly added credentials providers to the cache

S3CachedCredentialsProvidersReused

Total number of reused credentials provider from the cache

S3Clients

Number of created S3 clients.

S3CompleteMultipartUpload

Number of S3 API CompleteMultipartUpload calls.

S3CopyObject

Number of S3 API CopyObject calls.

S3CreateMultipartUpload

Number of S3 API CreateMultipartUpload calls.

S3DeleteObjects

Number of S3 API DeleteObject(s) calls.

S3GetObject

Number of S3 API GetObject calls.

S3GetObjectTagging

Number of S3 API GetObjectTagging calls.

S3GetRequestThrottlerBlocked

Number of S3 GET and SELECT requests blocked by throttler.

S3GetRequestThrottlerCount

Number of S3 GET and SELECT requests passed through throttler: blocked and not blocked.

S3GetRequestThrottlerSleepMicroseconds

Total time a query was sleeping to conform S3 GET and SELECT request throttling.

S3HeadObject

Number of S3 API HeadObject calls.

S3ListObjects

Number of S3 API ListObjects calls.

S3PutObject

Number of S3 API PutObject calls.

S3PutRequestThrottlerBlocked

Number of S3 PUT, COPY, POST and LIST requests blocked by throttler.

S3PutRequestThrottlerCount

Number of S3 PUT, COPY, POST and LIST requests passed through throttler: blocked and not blocked.

S3PutRequestThrottlerSleepMicroseconds

Total time a query was sleeping to conform S3 PUT, COPY, POST and LIST request throttling.

S3QueueSetFileFailedMicroseconds

Time spent to set file as failed

S3QueueSetFileProcessedMicroseconds

Time spent to set file as processed

S3QueueSetFileProcessingMicroseconds

Time spent to set file as processing

S3ReadMicroseconds

Time of GET and HEAD requests to S3 storage.

S3ReadRequestAttempts

Number of attempts for GET and HEAD requests, including the initial try and any retries, but excluding retries performed internally by the S3 retry strategy

S3ReadRequestRetryableErrors

Number of retryable errors for GET and HEAD requests, excluding retries performed internally by the S3 retry strategy

S3ReadRequestsCount

Number of GET and HEAD requests to S3 storage.

S3ReadRequestsErrors

Number of non-throttling errors in GET and HEAD requests to S3 storage.

S3ReadRequestsRedirects

Number of redirects in GET and HEAD requests to S3 storage.

S3ReadRequestsThrottling

Number of 429 and 503 errors in GET and HEAD requests to S3 storage.

S3UploadPart

Number of S3 API UploadPart calls.

S3UploadPartCopy

Number of S3 API UploadPartCopy calls.

S3WriteMicroseconds

Time of POST, DELETE, PUT and PATCH requests to S3 storage.

S3WriteRequestAttempts

Number of attempts for POST, DELETE, PUT and PATCH requests, including the initial try and any retries, but excluding retries performed internally by the retry strategy

S3WriteRequestRetryableErrors

Number of retryable errors for POST, DELETE, PUT and PATCH requests, excluding retries performed internally by the retry strategy

S3WriteRequestsCount

Number of POST, DELETE, PUT and PATCH requests to S3 storage.

S3WriteRequestsErrors

Number of non-throttling errors in POST, DELETE, PUT and PATCH requests to S3 storage.

S3WriteRequestsRedirects

Number of redirects in POST, DELETE, PUT and PATCH requests to S3 storage.

S3WriteRequestsThrottling

Number of 429 and 503 errors in POST, DELETE, PUT and PATCH requests to S3 storage.

ScalarSubqueriesCacheMiss

Number of times a read from a scalar subquery was not cached and had to be calculated completely

ScalarSubqueriesGlobalCacheHit

Number of times a read from a scalar subquery was done using the global cache

ScalarSubqueriesLocalCacheHit

Number of times a read from a scalar subquery was done using the local cache

SchedulerIOReadBytes

Bytes passed through scheduler for IO reads.

SchedulerIOReadRequests

Resource requests passed through scheduler for IO reads.

SchedulerIOReadWaitMicroseconds

Total time a query was waiting on resource requests for IO reads.

SchedulerIOWriteBytes

Bytes passed through scheduler for IO writes.

SchedulerIOWriteRequests

Resource requests passed through scheduler for IO writes.

SchedulerIOWriteWaitMicroseconds

Total time a query was waiting on resource requests for IO writes.

SchemaInferenceCacheEvictions

Number of times a schema from cache was evicted due to overflow

SchemaInferenceCacheHits

Number of times the requested source is found in schema cache

SchemaInferenceCacheInvalidations

Number of times a schema in cache became invalid due to changes in data

SchemaInferenceCacheMisses

Number of times the requested source is not in schema cache

SchemaInferenceCacheNumRowsHits

Number of times the number of rows is found in schema cache during count from files

SchemaInferenceCacheNumRowsMisses

Number of times the requested source is in cache but the number of rows is not in cache while count from files

SchemaInferenceCacheSchemaHits

Number of times the schema is found in schema cache during schema inference

SchemaInferenceCacheSchemaMisses

Number of times the requested source is in cache but the schema is not in cache during schema inference

Seek

Number of times the ‘lseek’ function was called.

SelectQueriesWithPrimaryKeyUsage

Count SELECT queries which use the primary key to evaluate the WHERE condition

SelectQueriesWithSubqueries

Count SELECT queries with all subqueries

SelectQuery

Same as Query, but only for SELECT queries.

SelectQueryTimeMicroseconds

Total time of SELECT queries.

SelectedBytes

Number of bytes (uncompressed; for columns as they stored in memory) SELECTed from all tables.

SelectedMarks

Number of marks (index granules) selected to read from a MergeTree table.

SelectedMarksTotal

Number of total marks (index granules) before selecting which ones to read from a MergeTree table.

SelectedParts

Number of data parts selected to read from a MergeTree table.

SelectedPartsTotal

Number of total data parts before selecting which ones to read from a MergeTree table.

SelectedRanges

Number of (non-adjacent) ranges in all data parts selected to read from a MergeTree table.

SelectedRows

Number of rows SELECTed from all tables.

SelfDuplicatedAsyncInserts

Number of async inserts in the INSERTed block to a ReplicatedMergeTree table was self deduplicated.

ServerStartupMilliseconds

Time elapsed from starting server to listening to sockets in milliseconds

Shards

The number of shards involved in a query, summed across all distributed tables and table functions. A single host is counted multiple times if it appears in multiple tables. The number counts the total expected number of shards, which includes skipped shards with the skip_unavailable_shards setting.

SharedDatabaseCatalogFailedToApplyState

Number of failures to apply new state in SharedDatabaseCatalog

SharedDatabaseCatalogStateApplicationMicroseconds

Total time spend on application of new state in SharedDatabaseCatalog

SharedMergeTreeCondemnedPartsKillRequest

How many ZooKeeper requests were used to remove condemned parts

SharedMergeTreeCondemnedPartsLockConflict

How many times we failed to acquite lock because of conflict

SharedMergeTreeCondemnedPartsRemoved

How many condemned parts were removed

SharedMergeTreeDataPartsFetchAttempt

How many times we tried to fetch data parts

SharedMergeTreeDataPartsFetchFromPeer

How many times we fetch data parts from peer

SharedMergeTreeDataPartsFetchFromPeerMicroseconds

Data parts fetch from peer microseconds

SharedMergeTreeDataPartsFetchFromS3

How many times we fetch data parts from S3

SharedMergeTreeHandleBlockingParts

How many blocking parts to handle in scheduleDataProcessingJob

SharedMergeTreeHandleBlockingPartsMicroseconds

Time of handling blocking parts in scheduleDataProcessingJob

SharedMergeTreeHandleFetchPartsMicroseconds

Time of handling fetched parts in scheduleDataProcessingJob

SharedMergeTreeHandleOutdatedParts

How many outdated parts to handle in scheduleDataProcessingJob

SharedMergeTreeHandleOutdatedPartsMicroseconds

Time of handling outdated parts in scheduleDataProcessingJob

SharedMergeTreeLoadChecksumAndIndexesMicroseconds

Time of loadColumnsChecksumsIndexes only for SharedMergeTree

SharedMergeTreeMergeMutationAssignmentAttempt

How many times we tried to assign merge or mutation

SharedMergeTreeMergeMutationAssignmentFailedWithConflict

How many times we tried to assign merge or mutation and failed because of conflict in Keeper

SharedMergeTreeMergeMutationAssignmentFailedWithNothingToDo

How many times we tried to assign merge or mutation and failed because nothing to merge

SharedMergeTreeMergeMutationAssignmentSuccessful

How many times we tried to assign merge or mutation

SharedMergeTreeMergePartsMovedToCondemned

How many parts moved to condemned directory

SharedMergeTreeMergePartsMovedToOudated

How many parts moved to oudated directory

SharedMergeTreeMergeSelectingTaskMicroseconds

Merge selecting task microseconds for SMT

SharedMergeTreeMetadataCacheHintLoadedFromCache

Number of times metadata cache hint was found without going to Keeper

SharedMergeTreeOptimizeAsync

Asynchronous OPTIMIZE queries executed

SharedMergeTreeOptimizeSync

Synchronous OPTIMIZE queries executed

SharedMergeTreeOutdatedPartsConfirmationInvocations

How many invocations were made to confirm outdated parts

SharedMergeTreeOutdatedPartsConfirmationRequest

How many ZooKeeper requests were used to config outdated parts

SharedMergeTreeOutdatedPartsHTTPRequest

How many HTTP requests were send to confirm outdated parts

SharedMergeTreeOutdatedPartsHTTPResponse

How many HTTP responses were send to confirm outdated parts

SharedMergeTreePartsKillerMicroseconds

How much time does parts killer main thread takes

SharedMergeTreePartsKillerParts

How many parts has been scheduled by the killer

SharedMergeTreePartsKillerPartsMicroseconds

How many time does it take to remove parts (executed from multiple threads)

SharedMergeTreePartsKillerRuns

How many times parts killer has been running

SharedMergeTreeReplicaSetUpdateTaskRuns

Number of times updateReplicaSetTask has run

SharedMergeTreeReplicaSetUpdatesFromZooKeeper

How many times we have update replica set from ZooKeeper

SharedMergeTreeReplicaSetUpdatesFromZooKeeperMicroseconds

How much time we spend to update replica set

SharedMergeTreeReplicaSetUpdatesFromZooKeeperRequests

How many total ZooKeeper requests we made to update replica set

SharedMergeTreeScheduleDataProcessingJob

How many times scheduleDataProcessingJob called/

SharedMergeTreeScheduleDataProcessingJobMicroseconds

scheduleDataProcessingJob execute time

SharedMergeTreeScheduleDataProcessingJobNothingToScheduled

How many times scheduleDataProcessingJob called but nothing to do

SharedMergeTreeSelectPartsForCoordinatedFetchMicroseconds

Time of selectPartsForCoordinatedFetch

SharedMergeTreeSelectPartsForCoordinatedFetchParts

Number of parts selected by selectPartsForCoordinatedFetch

SharedMergeTreeSelectPartsForFullFetchMicroseconds

Time of selectPartsForFullFetch

SharedMergeTreeSelectPartsForFullFetchParts

Number of parts selected by selectPartsForFullFetch

SharedMergeTreeSelectPartsForRendezvousFetchMicroseconds

Time of selectPartsForRendezvousFetch

SharedMergeTreeSelectPartsForRendezvousFetchParts

Number of parts selected by selectPartsForRendezvousFetch

SharedMergeTreeSnapshotPartsCleanRequest

How many times SnapshotCleanerThread decides to clean a part

SharedMergeTreeSnapshotPartsCleanerMicroseconds

How long time SnapshotCleanerThread has run

SharedMergeTreeSnapshotPartsCleanerParts

How long time SnapshotCleanerThread tries to clean a part

SharedMergeTreeSnapshotPartsCleanerPartsMicroseconds

How long time SnapshotCleanerThread takes to clean parts

SharedMergeTreeSnapshotPartsCleanerRuns

How many times SnapshotCleanerThread runs

SharedMergeTreeSnapshotPartsRemoved

How many times SnapshotCleanerThread successfully clean a part

SharedMergeTreeTryUpdateDiskMetadataCacheForPartMicroseconds

Time of tryUpdateDiskMetadataCacheForPart in scheduleDataProcessingJob

SharedMergeTreeVirtualPartsUpdateMicroseconds

Virtual parts update microseconds

SharedMergeTreeVirtualPartsUpdates

Virtual parts update count

SharedMergeTreeVirtualPartsUpdatesByLeader

Virtual parts updates by leader

SharedMergeTreeVirtualPartsUpdatesForMergesOrStatus

Virtual parts updates from non-default background job

SharedMergeTreeVirtualPartsUpdatesFromPeer

Virtual parts updates count from peer

SharedMergeTreeVirtualPartsUpdatesFromPeerMicroseconds

Virtual parts updates from peer microseconds

SharedMergeTreeVirtualPartsUpdatesFromZooKeeper

Virtual parts updates count from ZooKeeper

SharedMergeTreeVirtualPartsUpdatesFromZooKeeperMicroseconds

Virtual parts updates from ZooKeeper microseconds

SharedMergeTreeVirtualPartsUpdatesLeaderFailedElection

Virtual parts updates leader election failed

SharedMergeTreeVirtualPartsUpdatesLeaderSuccessfulElection

Virtual parts updates leader election successful

SharedMergeTreeVirtualPartsUpdatesPeerNotFound

Virtual updates from peer failed because no one found

SharedPartsLockHoldMicroseconds

Total time spent holding shared data parts lock in MergeTree tables

SharedPartsLockWaitMicroseconds

Total time spent waiting for shared data parts lock in MergeTree tables

SharedPartsLocks

Number of times shared data parts lock has been acquired for MergeTree tables

SleepFunctionCalls

Number of times a sleep function (sleep, sleepEachRow) has been called.

SleepFunctionElapsedMicroseconds

Time spent sleeping in a sleep function (sleep, sleepEachRow).

SleepFunctionMicroseconds

Time set to sleep in a sleep function (sleep, sleepEachRow).

SlowRead

Number of reads from a file that were slow. This indicate system overload. Thresholds are controlled by read_backoff_* settings.

SoftPageFaults

The number of soft page faults in query execution threads. Soft page fault usually means a miss in the memory allocator cache, which requires a new memory mapping from the OS and subsequent allocation of a page of physical memory.

StorageBufferErrorOnFlush

Number of times a buffer in the ‘Buffer’ table has not been able to flush due to error writing in the destination table.

StorageBufferFlush

Number of times a buffer in a ‘Buffer’ table was flushed.

StorageBufferLayerLockReadersWaitMilliseconds

Time for waiting for Buffer layer during reading.

StorageBufferLayerLockWritersWaitMilliseconds

Time for waiting free Buffer layer to write to (can be used to tune Buffer layers).

StorageBufferPassedAllMinThresholds

Number of times a criteria on min thresholds has been reached to flush a buffer in a ‘Buffer’ table.

StorageBufferPassedBytesFlushThreshold

Number of times background-only flush threshold on bytes has been reached to flush a buffer in a ‘Buffer’ table. This is expert-only metric. If you read this and you are not an expert, stop reading.

StorageBufferPassedBytesMaxThreshold

Number of times a criteria on max bytes threshold has been reached to flush a buffer in a ‘Buffer’ table.

StorageBufferPassedRowsFlushThreshold

Number of times background-only flush threshold on rows has been reached to flush a buffer in a ‘Buffer’ table. This is expert-only metric. If you read this and you are not an expert, stop reading.

StorageBufferPassedRowsMaxThreshold

Number of times a criteria on max rows threshold has been reached to flush a buffer in a ‘Buffer’ table.

StorageBufferPassedTimeFlushThreshold

Number of times background-only flush threshold on time has been reached to flush a buffer in a ‘Buffer’ table. This is expert-only metric. If you read this and you are not an expert, stop reading.

StorageBufferPassedTimeMaxThreshold

Number of times a criteria on max time threshold has been reached to flush a buffer in a ‘Buffer’ table.

StorageConnectionsCreated

Number of created connections for storages

StorageConnectionsElapsedMicroseconds

Total time spend on creating connections for storages

StorageConnectionsErrors

Number of cases when creation of a connection for storage is failed

StorageConnectionsExpired

Number of expired connections for storages

StorageConnectionsPreserved

Number of preserved connections for storages

StorageConnectionsReset

Number of reset connections for storages

StorageConnectionsReused

Number of reused connections for storages

SummingSortedMilliseconds

Total time spent while summing sorted columns

SuspendSendingQueryToShard

Total count when sending query to shard was suspended when async_query_sending_for_remote is enabled.

SynchronousReadWaitMicroseconds

Time spent in waiting for synchronous reads in asynchronous local read.

SynchronousRemoteReadWaitMicroseconds

Time spent in waiting for synchronous remote reads.

SystemLogErrorOnFlush

Number of times any of the system logs have failed to flush to the corresponding system table. Attempts to flush are repeated.

SystemTimeMicroseconds

Total time spent in processing (queries and other tasks) threads executing CPU instructions in OS kernel mode. This is time spent in syscalls, excluding waiting time during blocking syscalls.

TableFunctionExecute

Number of table function calls.

TextIndexDiscardHint

Number of index granules where a direct reading from the text index was added as hint and was discarded due to low selectivity.

TextIndexDiscardPatternScan

Number of times pattern-based dictionary scan in a text index was discarded because the number of posting lists to read exceeded the threshold.

TextIndexHeaderCacheHits

Number of times a header has been found in the cache.

TextIndexHeaderCacheMisses

Number of times a header has not been found in the cache.

TextIndexPostingsCacheHits

Number of times a text index posting list has been found in the cache.

TextIndexPostingsCacheMisses

Number of times a a text index posting list has not been found in the cache.

TextIndexReadDictionaryBlocks

Number of times a text index dictionary block has been read from disk.

TextIndexReadGranulesMicroseconds

Total time spent reading and analyzing granules of the text index.

TextIndexReadPostings

Number of times a posting list has been read from the text index.

TextIndexReadSparseIndexBlocks

Number of times a sparse index block has been read from the text index.

TextIndexReaderTotalMicroseconds

Total time spent reading the text index.

TextIndexTokensCacheHits

Number of times a text index token info has been found in the cache.

TextIndexTokensCacheMisses

Number of times a text index token info has not been found in the cache.

TextIndexUseHint

Number of index granules where a direct reading from the text index was added as hint and was used.

TextIndexUsedEmbeddedPostings

Number of times a posting list embedded in the dictionary has been used.

ThreadPoolReaderPageCacheHit

Number of times the read inside ThreadPoolReader was done from the page cache.

ThreadPoolReaderPageCacheHitBytes

Number of bytes read inside ThreadPoolReader when it was done from the page cache.

ThreadPoolReaderPageCacheHitElapsedMicroseconds

Time spent reading data from page cache in ThreadPoolReader.

ThreadPoolReaderPageCacheMiss

Number of times the read inside ThreadPoolReader was not done from page cache and was hand off to thread pool.

ThreadPoolReaderPageCacheMissBytes

Number of bytes read inside ThreadPoolReader when read was not done from page cache and was hand off to thread pool.

ThreadPoolReaderPageCacheMissElapsedMicroseconds

Time spent reading data inside the asynchronous job in ThreadPoolReader - when read was not done from the page cache.

ThreadpoolReaderPrepareMicroseconds

Time spent on preparation (e.g. call to reader seek() method)

ThreadpoolReaderReadBytes

Bytes read from a threadpool task in asynchronous reading

ThreadpoolReaderSubmit

Bytes read from a threadpool task in asynchronous reading

ThreadpoolReaderSubmitLookupInCacheMicroseconds

How much time we spent checking if content is cached

ThreadpoolReaderSubmitReadSynchronously

How many times we haven’t scheduled a task on the thread pool and read synchronously instead

ThreadpoolReaderSubmitReadSynchronouslyBytes

How many bytes were read synchronously

ThreadpoolReaderSubmitReadSynchronouslyMicroseconds

How much time we spent reading synchronously

ThreadpoolReaderTaskMicroseconds

Time spent getting the data in asynchronous reading

ThrottlerSleepMicroseconds

Total time a query was sleeping to conform all throttling settings.

TinyS3Clients

Number of S3 clients copies which reuse an existing auth provider from another client.

USearchAddComputedDistances

Number of times distance was computed when adding vectors to usearch indexes.

USearchAddCount

Number of vectors added to usearch indexes.

USearchAddVisitedMembers

Number of nodes visited when adding vectors to usearch indexes.

USearchSearchComputedDistances

Number of times distance was computed when searching usearch indexes.

USearchSearchCount

Number of search operations performed in usearch indexes.

USearchSearchVisitedMembers

Number of nodes visited when searching in usearch indexes.

UncompressedCacheHits

Number of times a block of data has been found in the uncompressed cache (and decompression was avoided).

UncompressedCacheMisses

Number of times a block of data has not been found in the uncompressed cache (and required decompression).

UncompressedCacheWeightLost

Number of bytes evicted from the uncompressed cache.

UserThrottlerBytes

Bytes passed through ‘max_network_bandwidth_for_user’ throttler.

UserThrottlerSleepMicroseconds

Total time a query was sleeping to conform ‘max_network_bandwidth_for_user’ throttling.

UserTimeMicroseconds

Total time spent in processing (queries and other tasks) threads executing CPU instructions in user mode. This includes time CPU pipeline was stalled due to main memory access, cache misses, branch mispredictions, hyper-threading, etc.

VectorSimilarityIndexCacheHits

Number of times an index granule has been found in the vector index cache.

VectorSimilarityIndexCacheMisses

Number of times an index granule has not been found in the vector index cache and had to be read from disk.

VectorSimilarityIndexCacheWeightLost

Approximate number of bytes evicted from the vector index cache.

VersionedCollapsingSortedMilliseconds

Total time spent while version collapsing sorted columns

WaitMarksLoadMicroseconds

Time spent loading marks

WaitPrefetchTaskMicroseconds

Time spend waiting for prefetched reader

WasmDeserializationMicroseconds

Time spent executing WebAssembly code

WasmGuestExecuteMicroseconds

Time spent executing WebAssembly code

WasmMemoryAllocated

Total memory allocated for WebAssembly compartments

WasmModuleInstatiate

Number of WebAssembly compartments created

WasmSerializationMicroseconds

Time spent executing WebAssembly code

WasmTotalExecuteMicroseconds

Time spent executing WebAssembly code

WriteBufferFromFileDescriptorWrite

Number of writes (write/pwrite) to a file descriptor. Does not include sockets.

WriteBufferFromFileDescriptorWriteBytes

Number of bytes written to file descriptors. If the file is compressed, this will show compressed data size.

WriteBufferFromFileDescriptorWriteFailed

Number of times the write (write/pwrite) to a file descriptor have failed.

WriteBufferFromHTTPBytes

Total size of payload bytes received and sent by WriteBufferFromHTTP. Doesn’t include HTTP headers.

WriteBufferFromHTTPRequestsSent

Number of HTTP requests sent by WriteBufferFromHTTP

WriteBufferFromS3Bytes

Bytes written to S3.

WriteBufferFromS3Microseconds

Time spent on writing to S3.

WriteBufferFromS3RequestsErrors

Number of exceptions while writing to S3.

WriteBufferFromS3WaitInflightLimitMicroseconds

Time spent on waiting while some of the current requests are done when its number reached the limit defined by s3_max_inflight_parts_for_one_file.

ZooKeeperBytesReceived

Number of bytes received over network while communicating with ZooKeeper.

ZooKeeperBytesSent

Number of bytes send over network while communicating with ZooKeeper.

ZooKeeperCheck

Number of ‘check’ requests to ZooKeeper. Usually they don’t make sense in isolation, only as part of a complex transaction.

ZooKeeperClose

Number of times connection with ZooKeeper has been closed voluntary.

ZooKeeperCreate

Number of ‘create’ requests to ZooKeeper.

ZooKeeperExists

Number of ‘exists’ requests to ZooKeeper.

ZooKeeperGet

Number of ‘get’ requests to ZooKeeper.

ZooKeeperGetACL

Number of ‘getACL’ requests to ZooKeeper.

ZooKeeperHardwareExceptions

Number of exceptions while working with ZooKeeper related to network (connection loss or similar).

ZooKeeperInit

Number of times connection with ZooKeeper has been established.

ZooKeeperList

Number of ‘list’ (getChildren) requests to ZooKeeper.

ZooKeeperListRecursive

Number of ‘listRecursive’ requests to ZooKeeper.

ZooKeeperMulti

Number of ‘multi’ requests to ZooKeeper (compound transactions).

ZooKeeperMultiRead

Number of read ‘multi’ requests to ZooKeeper (compound transactions).

ZooKeeperMultiWrite

Number of write ‘multi’ requests to ZooKeeper (compound transactions).

ZooKeeperOtherExceptions

Number of exceptions while working with ZooKeeper other than ZooKeeperUserExceptions and ZooKeeperHardwareExceptions.

ZooKeeperReconfig

Number of ‘reconfig’ requests to ZooKeeper.

ZooKeeperRemove

Number of ‘remove’ requests to ZooKeeper.

ZooKeeperSet

Number of ‘set’ requests to ZooKeeper.

ZooKeeperSync

Number of ‘sync’ requests to ZooKeeper. These requests are rarely needed or usable.

ZooKeeperTransactions

Number of ZooKeeper operations, which include both read and write operations as well as multi-transactions.

ZooKeeperUserExceptions

Number of exceptions while working with ZooKeeper related to the data (no node, bad version or similar).

ZooKeeperWaitMicroseconds

Number of microseconds spent waiting for responses from ZooKeeper after creating a request, summed across all the requesting threads.

ZooKeeperWatchResponse

Number of times watch notification has been received from ZooKeeper.

SQL Reference

Documentation Index

​Description

​Columns

​Example

​See Also

​Event descriptions

​ACMEAPIRequests

​ACMECertificateOrders

​AIAPICalls

​AIInputTokens

​AIORead

​AIOReadBytes

​AIOWrite

​AIOWriteBytes

​AIOutputTokens

​AIRowsProcessed

​AIRowsSkipped

​ASTFuzzerQueries

​AddressesDiscovered

​AddressesExpired

​AddressesMarkedAsFailed

​AggregatingSortedMilliseconds

​AggregationHashTablesInitializedAsTwoLevel

​AggregationOptimizedEqualRangesOfKeys

​AggregationPreallocatedElementsInHashTables

​AllUsersThrottlerBytes

​AllUsersThrottlerSleepMicroseconds

​AnalyzePatchRangesMicroseconds

​ApplyPatchesMicroseconds

​ArenaAllocBytes

​ArenaAllocChunks

​AsyncInsertBytes

​AsyncInsertCacheHits

​AsyncInsertQuery

​AsyncInsertRows

​AsyncLoaderWaitMicroseconds

​AsyncLoggingConsoleDroppedMessages

​AsyncLoggingConsoleTotalMessages

​AsyncLoggingErrorFileLogDroppedMessages

​AsyncLoggingErrorFileLogTotalMessages

​AsyncLoggingFileLogDroppedMessages

​AsyncLoggingFileLogTotalMessages

​AsyncLoggingSyslogDroppedMessages

​AsyncLoggingSyslogTotalMessages

​AsyncLoggingTextLogDroppedMessages

​AsyncLoggingTextLogTotalMessages

​AsynchronousReadWaitMicroseconds

​AsynchronousReaderIgnoredBytes

​AsynchronousRemoteReadWaitMicroseconds

​AzureCommitBlockList

​AzureCopyObject

​AzureCreateContainer

​AzureDeleteObjects

​AzureGetObject

​AzureGetProperties

​AzureGetRequestThrottlerBlocked

​AzureGetRequestThrottlerCount

​AzureGetRequestThrottlerSleepMicroseconds

​AzureListObjects

​AzurePutRequestThrottlerBlocked

​AzurePutRequestThrottlerCount

​AzurePutRequestThrottlerSleepMicroseconds

​AzureReadMicroseconds

​AzureReadRequestsCount

​AzureReadRequestsErrors

​AzureReadRequestsRedirects

​AzureReadRequestsThrottling

​AzureStageBlock

​AzureUpload

​AzureWriteMicroseconds

​AzureWriteRequestsCount

​AzureWriteRequestsErrors

​AzureWriteRequestsRedirects

​AzureWriteRequestsThrottling

​BackgroundLoadingMarksTasks

​BackupEntriesCollectorForTablesDataMicroseconds

​BackupEntriesCollectorMicroseconds

​BackupEntriesCollectorRunPostTasksMicroseconds

​BackupLockFileReads

Description

Columns

Example

See Also

Event descriptions

ACMEAPIRequests

ACMECertificateOrders

AIAPICalls

AIInputTokens

AIORead

AIOReadBytes

AIOWrite

AIOWriteBytes

AIOutputTokens

AIRowsProcessed

AIRowsSkipped

ASTFuzzerQueries

AddressesDiscovered

AddressesExpired

AddressesMarkedAsFailed

AggregatingSortedMilliseconds

AggregationHashTablesInitializedAsTwoLevel

AggregationOptimizedEqualRangesOfKeys

AggregationPreallocatedElementsInHashTables

AllUsersThrottlerBytes

AllUsersThrottlerSleepMicroseconds

AnalyzePatchRangesMicroseconds

ApplyPatchesMicroseconds

ArenaAllocBytes

ArenaAllocChunks

AsyncInsertBytes

AsyncInsertCacheHits

AsyncInsertQuery

AsyncInsertRows

AsyncLoaderWaitMicroseconds

AsyncLoggingConsoleDroppedMessages

AsyncLoggingConsoleTotalMessages

AsyncLoggingErrorFileLogDroppedMessages

AsyncLoggingErrorFileLogTotalMessages

AsyncLoggingFileLogDroppedMessages

AsyncLoggingFileLogTotalMessages

AsyncLoggingSyslogDroppedMessages

AsyncLoggingSyslogTotalMessages

AsyncLoggingTextLogDroppedMessages

AsyncLoggingTextLogTotalMessages

AsynchronousReadWaitMicroseconds

AsynchronousReaderIgnoredBytes

AsynchronousRemoteReadWaitMicroseconds

AzureCommitBlockList

AzureCopyObject

AzureCreateContainer

AzureDeleteObjects

AzureGetObject

AzureGetProperties

AzureGetRequestThrottlerBlocked

AzureGetRequestThrottlerCount

AzureGetRequestThrottlerSleepMicroseconds

AzureListObjects

AzurePutRequestThrottlerBlocked

AzurePutRequestThrottlerCount

AzurePutRequestThrottlerSleepMicroseconds

AzureReadMicroseconds

AzureReadRequestsCount

AzureReadRequestsErrors

AzureReadRequestsRedirects

AzureReadRequestsThrottling

AzureStageBlock

AzureUpload

AzureWriteMicroseconds

AzureWriteRequestsCount

AzureWriteRequestsErrors

AzureWriteRequestsRedirects

AzureWriteRequestsThrottling

BackgroundLoadingMarksTasks

BackupEntriesCollectorForTablesDataMicroseconds

BackupEntriesCollectorMicroseconds

BackupEntriesCollectorRunPostTasksMicroseconds

BackupLockFileReads

BackupPreparingFileInfosMicroseconds

BackupReadLocalBytesToCalculateChecksums